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1 \input texinfo @c -*-texinfo-*-
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2 @c %**start of header
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3 @setfilename ../info/standards.info
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4 @settitle GNU Coding Standards
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5 @c This date is automagically updated when you save this file:
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6 @set lastupdate June 24, 1999
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7 @c %**end of header
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8
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9 @ifinfo
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10 @format
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11 START-INFO-DIR-ENTRY
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12 * Standards: (standards). GNU coding standards.
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13 END-INFO-DIR-ENTRY
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14 @end format
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15 @end ifinfo
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16
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17 @c @setchapternewpage odd
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18 @setchapternewpage off
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19
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20 @c This is used by a cross ref in make-stds.texi
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21 @set CODESTD 1
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22 @iftex
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23 @set CHAPTER chapter
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24 @end iftex
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25 @ifinfo
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26 @set CHAPTER node
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27 @end ifinfo
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28
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29 @ifinfo
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30 GNU Coding Standards
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31 Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
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32
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33 Permission is granted to make and distribute verbatim copies of
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34 this manual provided the copyright notice and this permission notice
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35 are preserved on all copies.
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36
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37 @ignore
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38 Permission is granted to process this file through TeX and print the
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39 results, provided the printed document carries copying permission
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40 notice identical to this one except for the removal of this paragraph
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41 (this paragraph not being relevant to the printed manual).
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42 @end ignore
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43
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44 Permission is granted to copy and distribute modified versions of this
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45 manual under the conditions for verbatim copying, provided that the entire
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46 resulting derived work is distributed under the terms of a permission
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47 notice identical to this one.
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48
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49 Permission is granted to copy and distribute translations of this manual
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50 into another language, under the above conditions for modified versions,
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51 except that this permission notice may be stated in a translation approved
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52 by the Free Software Foundation.
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53 @end ifinfo
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54
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55 @titlepage
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56 @title GNU Coding Standards
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57 @author Richard Stallman
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58 @author last updated @value{lastupdate}
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59 @page
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60
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61 @vskip 0pt plus 1filll
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62 Copyright @copyright{} 1992, 1993, 1994, 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
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63
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64 Permission is granted to make and distribute verbatim copies of
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65 this manual provided the copyright notice and this permission notice
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66 are preserved on all copies.
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67
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68 Permission is granted to copy and distribute modified versions of this
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69 manual under the conditions for verbatim copying, provided that the entire
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70 resulting derived work is distributed under the terms of a permission
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71 notice identical to this one.
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72
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73 Permission is granted to copy and distribute translations of this manual
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74 into another language, under the above conditions for modified versions,
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75 except that this permission notice may be stated in a translation approved
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76 by the Free Software Foundation.
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77 @end titlepage
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78
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79 @ifinfo
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80 @node Top, Preface, (dir), (dir)
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81 @top Version
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82
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83 Last updated @value{lastupdate}.
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84 @end ifinfo
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85
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86 @menu
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87 * Preface:: About the GNU Coding Standards
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88 * Legal Issues:: Keeping Free Software Free
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89 * Design Advice:: General Program Design
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90 * Program Behavior:: Program Behavior for All Programs
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91 * Writing C:: Making The Best Use of C
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92 * Documentation:: Documenting Programs
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93 * Managing Releases:: The Release Process
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94 * References:: References to Non-Free Software or Documentation
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95 @end menu
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96
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97 @node Preface
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98 @chapter About the GNU Coding Standards
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99
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100 The GNU Coding Standards were written by Richard Stallman and other GNU
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101 Project volunteers. Their purpose is to make the GNU system clean,
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102 consistent, and easy to install. This document can also be read as a
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103 guide to writing portable, robust and reliable programs. It focuses on
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104 programs written in C, but many of the rules and principles are useful
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105 even if you write in another programming language. The rules often
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106 state reasons for writing in a certain way.
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107
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108 Corrections or suggestions for this document should be sent to
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109 @email{gnu@@gnu.org}. If you make a suggestion, please include a
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110 suggested new wording for it; our time is limited. We prefer a context
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111 diff to the @file{standards.texi} or @file{make-stds.texi} files, but if
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112 you don't have those files, please mail your suggestion anyway.
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113
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114 This release of the GNU Coding Standards was last updated
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115 @value{lastupdate}.
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116
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117 @node Legal Issues
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118 @chapter Keeping Free Software Free
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119
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120 This @value{CHAPTER} discusses how you can make sure that GNU software
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121 remains unencumbered.
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122
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123 @menu
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124 * Reading Non-Free Code:: Referring to Proprietary Programs
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125 * Contributions:: Accepting Contributions
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126 @end menu
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127
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128 @node Reading Non-Free Code
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129 @section Referring to Proprietary Programs
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130
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131 Don't in any circumstances refer to Unix source code for or during
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132 your work on GNU! (Or to any other proprietary programs.)
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133
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134 If you have a vague recollection of the internals of a Unix program,
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135 this does not absolutely mean you can't write an imitation of it, but
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136 do try to organize the imitation internally along different lines,
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137 because this is likely to make the details of the Unix version
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138 irrelevant and dissimilar to your results.
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139
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140 For example, Unix utilities were generally optimized to minimize
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141 memory use; if you go for speed instead, your program will be very
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142 different. You could keep the entire input file in core and scan it
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143 there instead of using stdio. Use a smarter algorithm discovered more
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144 recently than the Unix program. Eliminate use of temporary files. Do
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145 it in one pass instead of two (we did this in the assembler).
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146
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147 Or, on the contrary, emphasize simplicity instead of speed. For some
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148 applications, the speed of today's computers makes simpler algorithms
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149 adequate.
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150
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151 Or go for generality. For example, Unix programs often have static
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152 tables or fixed-size strings, which make for arbitrary limits; use
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153 dynamic allocation instead. Make sure your program handles NULs and
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154 other funny characters in the input files. Add a programming language
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155 for extensibility and write part of the program in that language.
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156
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157 Or turn some parts of the program into independently usable libraries.
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158 Or use a simple garbage collector instead of tracking precisely when
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159 to free memory, or use a new GNU facility such as obstacks.
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160
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161
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162 @node Contributions
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163 @section Accepting Contributions
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164
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165 If the program you are working on is copyrighted by the Free Software
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166 Foundation, then when someone else sends you a piece of code to add to
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167 the program, we need legal papers to use it---just as we asked you to
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168 sign papers initially. @emph{Each} person who makes a nontrivial
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169 contribution to a program must sign some sort of legal papers in order
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170 for us to have clear title to the program; the main author alone is not
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171 enough.
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172
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173 So, before adding in any contributions from other people, please tell
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174 us, so we can arrange to get the papers. Then wait until we tell you
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175 that we have received the signed papers, before you actually use the
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176 contribution.
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177
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178 This applies both before you release the program and afterward. If
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179 you receive diffs to fix a bug, and they make significant changes, we
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180 need legal papers for that change.
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181
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182 This also applies to comments and documentation files. For copyright
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183 law, comments and code are just text. Copyright applies to all kinds of
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184 text, so we need legal papers for all kinds.
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185
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186 We know it is frustrating to ask for legal papers; it's frustrating for
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187 us as well. But if you don't wait, you are going out on a limb---for
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188 example, what if the contributor's employer won't sign a disclaimer?
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189 You might have to take that code out again!
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190
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191 You don't need papers for changes of a few lines here or there, since
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192 they are not significant for copyright purposes. Also, you don't need
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193 papers if all you get from the suggestion is some ideas, not actual code
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194 which you use. For example, if someone send you one implementation, but
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195 you write a different implementation of the same idea, you don't need to
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196 get papers.
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197
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198 The very worst thing is if you forget to tell us about the other
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199 contributor. We could be very embarrassed in court some day as a
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200 result.
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201
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202 We have more detailed advice for maintainers of programs; if you have
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203 reached the stage of actually maintaining a program for GNU (whether
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204 released or not), please ask us for a copy.
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205
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206 @node Design Advice
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207 @chapter General Program Design
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208
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209 This @value{CHAPTER} discusses some of the issues you should take into
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210 account when designing your program.
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211
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212 @menu
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213 * Compatibility:: Compatibility with other implementations
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214 * Using Extensions:: Using non-standard features
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215 * ANSI C:: Using ANSI C features
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216 * Source Language:: Using languages other than C
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217 @end menu
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218
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219 @node Compatibility
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220 @section Compatibility with Other Implementations
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221
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222 With occasional exceptions, utility programs and libraries for GNU
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223 should be upward compatible with those in Berkeley Unix, and upward
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224 compatible with @sc{ansi} C if @sc{ansi} C specifies their behavior, and
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225 upward compatible with @sc{posix} if @sc{posix} specifies their
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226 behavior.
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227
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228 When these standards conflict, it is useful to offer compatibility
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229 modes for each of them.
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230
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231 @sc{ansi} C and @sc{posix} prohibit many kinds of extensions. Feel free
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232 to make the extensions anyway, and include a @samp{--ansi},
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233 @samp{--posix}, or @samp{--compatible} option to turn them off.
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234 However, if the extension has a significant chance of breaking any real
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235 programs or scripts, then it is not really upward compatible. Try to
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236 redesign its interface.
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237
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238 Many GNU programs suppress extensions that conflict with @sc{posix} if the
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239 environment variable @code{POSIXLY_CORRECT} is defined (even if it is
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240 defined with a null value). Please make your program recognize this
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241 variable if appropriate.
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242
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243 When a feature is used only by users (not by programs or command
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244 files), and it is done poorly in Unix, feel free to replace it
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245 completely with something totally different and better. (For example,
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246 @code{vi} is replaced with Emacs.) But it is nice to offer a compatible
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247 feature as well. (There is a free @code{vi} clone, so we offer it.)
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248
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249 Additional useful features not in Berkeley Unix are welcome.
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250
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251 @node Using Extensions
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252 @section Using Non-standard Features
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253
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254 Many GNU facilities that already exist support a number of convenient
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255 extensions over the comparable Unix facilities. Whether to use these
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256 extensions in implementing your program is a difficult question.
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257
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258 On the one hand, using the extensions can make a cleaner program.
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259 On the other hand, people will not be able to build the program
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260 unless the other GNU tools are available. This might cause the
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261 program to work on fewer kinds of machines.
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262
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263 With some extensions, it might be easy to provide both alternatives.
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264 For example, you can define functions with a ``keyword'' @code{INLINE}
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265 and define that as a macro to expand into either @code{inline} or
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266 nothing, depending on the compiler.
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267
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268 In general, perhaps it is best not to use the extensions if you can
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269 straightforwardly do without them, but to use the extensions if they
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270 are a big improvement.
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271
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272 An exception to this rule are the large, established programs (such as
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273 Emacs) which run on a great variety of systems. Such programs would
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274 be broken by use of GNU extensions.
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275
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276 Another exception is for programs that are used as part of
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277 compilation: anything that must be compiled with other compilers in
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278 order to bootstrap the GNU compilation facilities. If these require
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279 the GNU compiler, then no one can compile them without having them
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280 installed already. That would be no good.
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281
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282 @node ANSI C
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283 @section @sc{ansi} C and pre-@sc{ansi} C
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284
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285 Do not ever use the ``trigraph'' feature of @sc{ansi} C.
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286
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287 @sc{ansi} C is widespread enough now that it is ok to write new programs
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288 that use @sc{ansi} C features (and therefore will not work in
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289 non-@sc{ansi} compilers). And if a program is already written in
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290 @sc{ansi} C, there's no need to convert it to support non-@sc{ansi}
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291 compilers.
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292
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293 If you don't know non-@sc{ansi} C, there's no need to learn it; just
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294 write in @sc{ansi} C.
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295
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296 However, it is easy to support non-@sc{ansi} compilers in most programs,
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297 so you might still consider doing so when you write a program. And if a
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298 program you are maintaining has such support, you should try to keep it
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299 working.
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300
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301 To support pre-@sc{ansi} C, instead of writing function definitions in
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302 @sc{ansi} prototype form,
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303
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304 @example
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305 int
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306 foo (int x, int y)
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307 @dots{}
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308 @end example
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309
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310 @noindent
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311 write the definition in pre-@sc{ansi} style like this,
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312
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313 @example
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314 int
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315 foo (x, y)
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316 int x, y;
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317 @dots{}
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318 @end example
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319
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320 @noindent
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321 and use a separate declaration to specify the argument prototype:
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322
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323 @example
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324 int foo (int, int);
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325 @end example
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326
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327 You need such a declaration anyway, in a header file, to get the benefit
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328 of @sc{ansi} C prototypes in all the files where the function is called.
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329 And once you have the declaration, you normally lose nothing by writing
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330 the function definition in the pre-@sc{ansi} style.
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331
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332 This technique does not work for integer types narrower than @code{int}.
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333 If you think of an argument as being of a type narrower than @code{int},
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334 declare it as @code{int} instead.
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335
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336 There are a few special cases where this technique is hard to use. For
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337 example, if a function argument needs to hold the system type
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338 @code{dev_t}, you run into trouble, because @code{dev_t} is shorter than
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339 @code{int} on some machines; but you cannot use @code{int} instead,
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340 because @code{dev_t} is wider than @code{int} on some machines. There
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341 is no type you can safely use on all machines in a non-@sc{ansi}
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342 definition. The only way to support non-@sc{ansi} C and pass such an
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343 argument is to check the width of @code{dev_t} using Autoconf and choose
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344 the argument type accordingly. This may not be worth the trouble.
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345
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346 @node Source Language
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347 @section Using Languages Other Than C
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348
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349 Using a language other than C is like using a non-standard feature: it
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350 will cause trouble for users. Even if GCC supports the other language,
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351 users may find it inconvenient to have to install the compiler for that
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352 other language in order to build your program. For example, if you
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353 write your program in C++, people will have to install the C++ compiler
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354 in order to compile your program. Thus, it is better if you write in C.
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355
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356 But there are three situations when there is no disadvantage in using
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357 some other language:
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358
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359 @itemize @bullet
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360 @item
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361 It is okay to use another language if your program contains an
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362 interpreter for that language.
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363
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364 For example, if your program links with GUILE, it is ok to write part of
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365 the program in Scheme or another language supported by GUILE.
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366
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367 @item
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368 It is okay to use another language in a tool specifically intended for
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369 use with that language.
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370
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371 This is okay because the only people who want to build the tool will be
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372 those who have installed the other language anyway.
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373
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374 @item
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375 If an application is of interest to a narrow community, then perhaps
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376 it's not important if the application is inconvenient to install.
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377 @end itemize
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378
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379 C has one other advantage over C++ and other compiled languages: more
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380 people know C, so more people will find it easy to read and modify the
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381 program if it is written in C.
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382
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383 @node Program Behavior
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384 @chapter Program Behavior for All Programs
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385
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386 This @value{CHAPTER} describes how to write robust software. It also
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387 describes general standards for error messages, the command line interface,
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388 and how libraries should behave.
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389
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390 @menu
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391 * Semantics:: Writing robust programs
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392 * Libraries:: Library behavior
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393 * Errors:: Formatting error messages
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394 * User Interfaces:: Standards for command line interfaces
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395 * Option Table:: Table of long options.
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396 * Memory Usage:: When and how to care about memory needs
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397 @end menu
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398
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399 @node Semantics
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400 @section Writing Robust Programs
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401
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402 Avoid arbitrary limits on the length or number of @emph{any} data
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403 structure, including file names, lines, files, and symbols, by allocating
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404 all data structures dynamically. In most Unix utilities, ``long lines
|
|
|
405 are silently truncated''. This is not acceptable in a GNU utility.
|
|
|
406
|
|
|
407 Utilities reading files should not drop NUL characters, or any other
|
|
|
408 nonprinting characters @emph{including those with codes above 0177}.
|
|
|
409 The only sensible exceptions would be utilities specifically intended
|
|
|
410 for interface to certain types of terminals or printers
|
|
|
411 that can't handle those characters.
|
|
|
412 Whenever possible, try to make programs work properly with
|
|
|
413 sequences of bytes that represent multibyte characters, using encodings
|
|
|
414 such as UTF-8 and others.
|
|
|
415
|
|
|
416 Check every system call for an error return, unless you know you wish to
|
|
|
417 ignore errors. Include the system error text (from @code{perror} or
|
|
|
418 equivalent) in @emph{every} error message resulting from a failing
|
|
|
419 system call, as well as the name of the file if any and the name of the
|
|
|
420 utility. Just ``cannot open foo.c'' or ``stat failed'' is not
|
|
|
421 sufficient.
|
|
|
422
|
|
|
423 Check every call to @code{malloc} or @code{realloc} to see if it
|
|
|
424 returned zero. Check @code{realloc} even if you are making the block
|
|
|
425 smaller; in a system that rounds block sizes to a power of 2,
|
|
|
426 @code{realloc} may get a different block if you ask for less space.
|
|
|
427
|
|
|
428 In Unix, @code{realloc} can destroy the storage block if it returns
|
|
|
429 zero. GNU @code{realloc} does not have this bug: if it fails, the
|
|
|
430 original block is unchanged. Feel free to assume the bug is fixed. If
|
|
|
431 you wish to run your program on Unix, and wish to avoid lossage in this
|
|
|
432 case, you can use the GNU @code{malloc}.
|
|
|
433
|
|
|
434 You must expect @code{free} to alter the contents of the block that was
|
|
|
435 freed. Anything you want to fetch from the block, you must fetch before
|
|
|
436 calling @code{free}.
|
|
|
437
|
|
|
438 If @code{malloc} fails in a noninteractive program, make that a fatal
|
|
|
439 error. In an interactive program (one that reads commands from the
|
|
|
440 user), it is better to abort the command and return to the command
|
|
|
441 reader loop. This allows the user to kill other processes to free up
|
|
|
442 virtual memory, and then try the command again.
|
|
|
443
|
|
|
444 Use @code{getopt_long} to decode arguments, unless the argument syntax
|
|
|
445 makes this unreasonable.
|
|
|
446
|
|
|
447 When static storage is to be written in during program execution, use
|
|
|
448 explicit C code to initialize it. Reserve C initialized declarations
|
|
|
449 for data that will not be changed.
|
|
|
450 @c ADR: why?
|
|
|
451
|
|
|
452 Try to avoid low-level interfaces to obscure Unix data structures (such
|
|
|
453 as file directories, utmp, or the layout of kernel memory), since these
|
|
|
454 are less likely to work compatibly. If you need to find all the files
|
|
|
455 in a directory, use @code{readdir} or some other high-level interface.
|
|
|
456 These are supported compatibly by GNU.
|
|
|
457
|
|
|
458 The preferred signal handling facilities are the BSD variant of
|
|
|
459 @code{signal}, and the @sc{posix} @code{sigaction} function; the
|
|
|
460 alternative USG @code{signal} interface is an inferior design.
|
|
|
461
|
|
|
462 Nowadays, using the @sc{posix} signal functions may be the easiest way
|
|
|
463 to make a program portable. If you use @code{signal}, then on GNU/Linux
|
|
|
464 systems running GNU libc version 1, you should include
|
|
|
465 @file{bsd/signal.h} instead of @file{signal.h}, so as to get BSD
|
|
|
466 behavior. It is up to you whether to support systems where
|
|
|
467 @code{signal} has only the USG behavior, or give up on them.
|
|
|
468
|
|
|
469 In error checks that detect ``impossible'' conditions, just abort.
|
|
|
470 There is usually no point in printing any message. These checks
|
|
|
471 indicate the existence of bugs. Whoever wants to fix the bugs will have
|
|
|
472 to read the source code and run a debugger. So explain the problem with
|
|
|
473 comments in the source. The relevant data will be in variables, which
|
|
|
474 are easy to examine with the debugger, so there is no point moving them
|
|
|
475 elsewhere.
|
|
|
476
|
|
|
477 Do not use a count of errors as the exit status for a program.
|
|
|
478 @emph{That does not work}, because exit status values are limited to 8
|
|
|
479 bits (0 through 255). A single run of the program might have 256
|
|
|
480 errors; if you try to return 256 as the exit status, the parent process
|
|
|
481 will see 0 as the status, and it will appear that the program succeeded.
|
|
|
482
|
|
|
483 If you make temporary files, check the @code{TMPDIR} environment
|
|
|
484 variable; if that variable is defined, use the specified directory
|
|
|
485 instead of @file{/tmp}.
|
|
|
486
|
|
|
487 @node Libraries
|
|
|
488 @section Library Behavior
|
|
|
489
|
|
|
490 Try to make library functions reentrant. If they need to do dynamic
|
|
|
491 storage allocation, at least try to avoid any nonreentrancy aside from
|
|
|
492 that of @code{malloc} itself.
|
|
|
493
|
|
|
494 Here are certain name conventions for libraries, to avoid name
|
|
|
495 conflicts.
|
|
|
496
|
|
|
497 Choose a name prefix for the library, more than two characters long.
|
|
|
498 All external function and variable names should start with this
|
|
|
499 prefix. In addition, there should only be one of these in any given
|
|
|
500 library member. This usually means putting each one in a separate
|
|
|
501 source file.
|
|
|
502
|
|
|
503 An exception can be made when two external symbols are always used
|
|
|
504 together, so that no reasonable program could use one without the
|
|
|
505 other; then they can both go in the same file.
|
|
|
506
|
|
|
507 External symbols that are not documented entry points for the user
|
|
|
508 should have names beginning with @samp{_}. They should also contain
|
|
|
509 the chosen name prefix for the library, to prevent collisions with
|
|
|
510 other libraries. These can go in the same files with user entry
|
|
|
511 points if you like.
|
|
|
512
|
|
|
513 Static functions and variables can be used as you like and need not
|
|
|
514 fit any naming convention.
|
|
|
515
|
|
|
516 @node Errors
|
|
|
517 @section Formatting Error Messages
|
|
|
518
|
|
|
519 Error messages from compilers should look like this:
|
|
|
520
|
|
|
521 @example
|
|
|
522 @var{source-file-name}:@var{lineno}: @var{message}
|
|
|
523 @end example
|
|
|
524
|
|
|
525 @noindent
|
|
|
526 If you want to mention the column number, use this format:
|
|
|
527
|
|
|
528 @example
|
|
|
529 @var{source-file-name}:@var{lineno}:@var{column}: @var{message}
|
|
|
530 @end example
|
|
|
531
|
|
|
532 @noindent
|
|
|
533 Line numbers should start from 1 at the beginning of the file, and
|
|
|
534 column numbers should start from 1 at the beginning of the line. (Both
|
|
|
535 of these conventions are chosen for compatibility.) Calculate column
|
|
|
536 numbers assuming that space and all ASCII printing characters have
|
|
|
537 equal width, and assuming tab stops every 8 columns.
|
|
|
538
|
|
|
539 Error messages from other noninteractive programs should look like this:
|
|
|
540
|
|
|
541 @example
|
|
|
542 @var{program}:@var{source-file-name}:@var{lineno}: @var{message}
|
|
|
543 @end example
|
|
|
544
|
|
|
545 @noindent
|
|
|
546 when there is an appropriate source file, or like this:
|
|
|
547
|
|
|
548 @example
|
|
|
549 @var{program}: @var{message}
|
|
|
550 @end example
|
|
|
551
|
|
|
552 @noindent
|
|
|
553 when there is no relevant source file.
|
|
|
554
|
|
|
555 If you want to mention the column number, use this format:
|
|
|
556
|
|
|
557 @example
|
|
|
558 @var{program}:@var{source-file-name}:@var{lineno}:@var{column}: @var{message}
|
|
|
559 @end example
|
|
|
560
|
|
|
561 In an interactive program (one that is reading commands from a
|
|
|
562 terminal), it is better not to include the program name in an error
|
|
|
563 message. The place to indicate which program is running is in the
|
|
|
564 prompt or with the screen layout. (When the same program runs with
|
|
|
565 input from a source other than a terminal, it is not interactive and
|
|
|
566 would do best to print error messages using the noninteractive style.)
|
|
|
567
|
|
|
568 The string @var{message} should not begin with a capital letter when
|
|
|
569 it follows a program name and/or file name. Also, it should not end
|
|
|
570 with a period.
|
|
|
571
|
|
|
572 Error messages from interactive programs, and other messages such as
|
|
|
573 usage messages, should start with a capital letter. But they should not
|
|
|
574 end with a period.
|
|
|
575
|
|
|
576 @node User Interfaces
|
|
|
577 @section Standards for Command Line Interfaces
|
|
|
578
|
|
|
579 Please don't make the behavior of a utility depend on the name used
|
|
|
580 to invoke it. It is useful sometimes to make a link to a utility
|
|
|
581 with a different name, and that should not change what it does.
|
|
|
582
|
|
|
583 Instead, use a run time option or a compilation switch or both
|
|
|
584 to select among the alternate behaviors.
|
|
|
585
|
|
|
586 Likewise, please don't make the behavior of the program depend on the
|
|
|
587 type of output device it is used with. Device independence is an
|
|
|
588 important principle of the system's design; do not compromise it merely
|
|
|
589 to save someone from typing an option now and then. (Variation in error
|
|
|
590 message syntax when using a terminal is ok, because that is a side issue
|
|
|
591 that people do not depend on.)
|
|
|
592
|
|
|
593 If you think one behavior is most useful when the output is to a
|
|
|
594 terminal, and another is most useful when the output is a file or a
|
|
|
595 pipe, then it is usually best to make the default behavior the one that
|
|
|
596 is useful with output to a terminal, and have an option for the other
|
|
|
597 behavior.
|
|
|
598
|
|
|
599 Compatibility requires certain programs to depend on the type of output
|
|
|
600 device. It would be disastrous if @code{ls} or @code{sh} did not do so
|
|
|
601 in the way all users expect. In some of these cases, we supplement the
|
|
|
602 program with a preferred alternate version that does not depend on the
|
|
|
603 output device type. For example, we provide a @code{dir} program much
|
|
|
604 like @code{ls} except that its default output format is always
|
|
|
605 multi-column format.
|
|
|
606
|
|
|
607 It is a good idea to follow the @sc{posix} guidelines for the
|
|
|
608 command-line options of a program. The easiest way to do this is to use
|
|
|
609 @code{getopt} to parse them. Note that the GNU version of @code{getopt}
|
|
|
610 will normally permit options anywhere among the arguments unless the
|
|
|
611 special argument @samp{--} is used. This is not what @sc{posix}
|
|
|
612 specifies; it is a GNU extension.
|
|
|
613
|
|
|
614 Please define long-named options that are equivalent to the
|
|
|
615 single-letter Unix-style options. We hope to make GNU more user
|
|
|
616 friendly this way. This is easy to do with the GNU function
|
|
|
617 @code{getopt_long}.
|
|
|
618
|
|
|
619 One of the advantages of long-named options is that they can be
|
|
|
620 consistent from program to program. For example, users should be able
|
|
|
621 to expect the ``verbose'' option of any GNU program which has one, to be
|
|
|
622 spelled precisely @samp{--verbose}. To achieve this uniformity, look at
|
|
|
623 the table of common long-option names when you choose the option names
|
|
|
624 for your program (@pxref{Option Table}).
|
|
|
625
|
|
|
626 It is usually a good idea for file names given as ordinary arguments to
|
|
|
627 be input files only; any output files would be specified using options
|
|
|
628 (preferably @samp{-o} or @samp{--output}). Even if you allow an output
|
|
|
629 file name as an ordinary argument for compatibility, try to provide an
|
|
|
630 option as another way to specify it. This will lead to more consistency
|
|
|
631 among GNU utilities, and fewer idiosyncracies for users to remember.
|
|
|
632
|
|
|
633 All programs should support two standard options: @samp{--version}
|
|
|
634 and @samp{--help}.
|
|
|
635
|
|
|
636 @table @code
|
|
|
637 @item --version
|
|
|
638 This option should direct the program to print information about its name,
|
|
|
639 version, origin and legal status, all on standard output, and then exit
|
|
|
640 successfully. Other options and arguments should be ignored once this
|
|
|
641 is seen, and the program should not perform its normal function.
|
|
|
642
|
|
|
643 The first line is meant to be easy for a program to parse; the version
|
|
|
644 number proper starts after the last space. In addition, it contains
|
|
|
645 the canonical name for this program, in this format:
|
|
|
646
|
|
|
647 @example
|
|
|
648 GNU Emacs 19.30
|
|
|
649 @end example
|
|
|
650
|
|
|
651 @noindent
|
|
|
652 The program's name should be a constant string; @emph{don't} compute it
|
|
|
653 from @code{argv[0]}. The idea is to state the standard or canonical
|
|
|
654 name for the program, not its file name. There are other ways to find
|
|
|
655 out the precise file name where a command is found in @code{PATH}.
|
|
|
656
|
|
|
657 If the program is a subsidiary part of a larger package, mention the
|
|
|
658 package name in parentheses, like this:
|
|
|
659
|
|
|
660 @example
|
|
|
661 emacsserver (GNU Emacs) 19.30
|
|
|
662 @end example
|
|
|
663
|
|
|
664 @noindent
|
|
|
665 If the package has a version number which is different from this
|
|
|
666 program's version number, you can mention the package version number
|
|
|
667 just before the close-parenthesis.
|
|
|
668
|
|
|
669 If you @strong{need} to mention the version numbers of libraries which
|
|
|
670 are distributed separately from the package which contains this program,
|
|
|
671 you can do so by printing an additional line of version info for each
|
|
|
672 library you want to mention. Use the same format for these lines as for
|
|
|
673 the first line.
|
|
|
674
|
|
|
675 Please do not mention all of the libraries that the program uses ``just
|
|
|
676 for completeness''---that would produce a lot of unhelpful clutter.
|
|
|
677 Please mention library version numbers only if you find in practice that
|
|
|
678 they are very important to you in debugging.
|
|
|
679
|
|
|
680 The following line, after the version number line or lines, should be a
|
|
|
681 copyright notice. If more than one copyright notice is called for, put
|
|
|
682 each on a separate line.
|
|
|
683
|
|
|
684 Next should follow a brief statement that the program is free software,
|
|
|
685 and that users are free to copy and change it on certain conditions. If
|
|
|
686 the program is covered by the GNU GPL, say so here. Also mention that
|
|
|
687 there is no warranty, to the extent permitted by law.
|
|
|
688
|
|
|
689 It is ok to finish the output with a list of the major authors of the
|
|
|
690 program, as a way of giving credit.
|
|
|
691
|
|
|
692 Here's an example of output that follows these rules:
|
|
|
693
|
|
|
694 @smallexample
|
|
|
695 GNU Emacs 19.34.5
|
|
|
696 Copyright (C) 1996 Free Software Foundation, Inc.
|
|
|
697 GNU Emacs comes with NO WARRANTY,
|
|
|
698 to the extent permitted by law.
|
|
|
699 You may redistribute copies of GNU Emacs
|
|
|
700 under the terms of the GNU General Public License.
|
|
|
701 For more information about these matters,
|
|
|
702 see the files named COPYING.
|
|
|
703 @end smallexample
|
|
|
704
|
|
|
705 You should adapt this to your program, of course, filling in the proper
|
|
|
706 year, copyright holder, name of program, and the references to
|
|
|
707 distribution terms, and changing the rest of the wording as necessary.
|
|
|
708
|
|
|
709 This copyright notice only needs to mention the most recent year in
|
|
|
710 which changes were made---there's no need to list the years for previous
|
|
|
711 versions' changes. You don't have to mention the name of the program in
|
|
|
712 these notices, if that is inconvenient, since it appeared in the first
|
|
|
713 line.
|
|
|
714
|
|
|
715 @item --help
|
|
|
716 This option should output brief documentation for how to invoke the
|
|
|
717 program, on standard output, then exit successfully. Other options and
|
|
|
718 arguments should be ignored once this is seen, and the program should
|
|
|
719 not perform its normal function.
|
|
|
720
|
|
|
721 Near the end of the @samp{--help} option's output there should be a line
|
|
|
722 that says where to mail bug reports. It should have this format:
|
|
|
723
|
|
|
724 @example
|
|
|
725 Report bugs to @var{mailing-address}.
|
|
|
726 @end example
|
|
|
727 @end table
|
|
|
728
|
|
|
729 @node Option Table
|
|
|
730 @section Table of Long Options
|
|
|
731
|
|
|
732 Here is a table of long options used by GNU programs. It is surely
|
|
|
733 incomplete, but we aim to list all the options that a new program might
|
|
|
734 want to be compatible with. If you use names not already in the table,
|
|
|
735 please send @email{gnu@@gnu.org} a list of them, with their
|
|
|
736 meanings, so we can update the table.
|
|
|
737
|
|
|
738 @c Please leave newlines between items in this table; it's much easier
|
|
|
739 @c to update when it isn't completely squashed together and unreadable.
|
|
|
740 @c When there is more than one short option for a long option name, put
|
|
|
741 @c a semicolon between the lists of the programs that use them, not a
|
|
|
742 @c period. --friedman
|
|
|
743
|
|
|
744 @table @samp
|
|
|
745 @item after-date
|
|
|
746 @samp{-N} in @code{tar}.
|
|
|
747
|
|
|
748 @item all
|
|
|
749 @samp{-a} in @code{du}, @code{ls}, @code{nm}, @code{stty}, @code{uname},
|
|
|
750 and @code{unexpand}.
|
|
|
751
|
|
|
752 @item all-text
|
|
|
753 @samp{-a} in @code{diff}.
|
|
|
754
|
|
|
755 @item almost-all
|
|
|
756 @samp{-A} in @code{ls}.
|
|
|
757
|
|
|
758 @item append
|
|
|
759 @samp{-a} in @code{etags}, @code{tee}, @code{time};
|
|
|
760 @samp{-r} in @code{tar}.
|
|
|
761
|
|
|
762 @item archive
|
|
|
763 @samp{-a} in @code{cp}.
|
|
|
764
|
|
|
765 @item archive-name
|
|
|
766 @samp{-n} in @code{shar}.
|
|
|
767
|
|
|
768 @item arglength
|
|
|
769 @samp{-l} in @code{m4}.
|
|
|
770
|
|
|
771 @item ascii
|
|
|
772 @samp{-a} in @code{diff}.
|
|
|
773
|
|
|
774 @item assign
|
|
|
775 @samp{-v} in @code{gawk}.
|
|
|
776
|
|
|
777 @item assume-new
|
|
|
778 @samp{-W} in Make.
|
|
|
779
|
|
|
780 @item assume-old
|
|
|
781 @samp{-o} in Make.
|
|
|
782
|
|
|
783 @item auto-check
|
|
|
784 @samp{-a} in @code{recode}.
|
|
|
785
|
|
|
786 @item auto-pager
|
|
|
787 @samp{-a} in @code{wdiff}.
|
|
|
788
|
|
|
789 @item auto-reference
|
|
|
790 @samp{-A} in @code{ptx}.
|
|
|
791
|
|
|
792 @item avoid-wraps
|
|
|
793 @samp{-n} in @code{wdiff}.
|
|
|
794
|
|
|
795 @item background
|
|
|
796 For server programs, run in the background.
|
|
|
797
|
|
|
798 @item backward-search
|
|
|
799 @samp{-B} in @code{ctags}.
|
|
|
800
|
|
|
801 @item basename
|
|
|
802 @samp{-f} in @code{shar}.
|
|
|
803
|
|
|
804 @item batch
|
|
|
805 Used in GDB.
|
|
|
806
|
|
|
807 @item baud
|
|
|
808 Used in GDB.
|
|
|
809
|
|
|
810 @item before
|
|
|
811 @samp{-b} in @code{tac}.
|
|
|
812
|
|
|
813 @item binary
|
|
|
814 @samp{-b} in @code{cpio} and @code{diff}.
|
|
|
815
|
|
|
816 @item bits-per-code
|
|
|
817 @samp{-b} in @code{shar}.
|
|
|
818
|
|
|
819 @item block-size
|
|
|
820 Used in @code{cpio} and @code{tar}.
|
|
|
821
|
|
|
822 @item blocks
|
|
|
823 @samp{-b} in @code{head} and @code{tail}.
|
|
|
824
|
|
|
825 @item break-file
|
|
|
826 @samp{-b} in @code{ptx}.
|
|
|
827
|
|
|
828 @item brief
|
|
|
829 Used in various programs to make output shorter.
|
|
|
830
|
|
|
831 @item bytes
|
|
|
832 @samp{-c} in @code{head}, @code{split}, and @code{tail}.
|
|
|
833
|
|
|
834 @item c@t{++}
|
|
|
835 @samp{-C} in @code{etags}.
|
|
|
836
|
|
|
837 @item catenate
|
|
|
838 @samp{-A} in @code{tar}.
|
|
|
839
|
|
|
840 @item cd
|
|
|
841 Used in various programs to specify the directory to use.
|
|
|
842
|
|
|
843 @item changes
|
|
|
844 @samp{-c} in @code{chgrp} and @code{chown}.
|
|
|
845
|
|
|
846 @item classify
|
|
|
847 @samp{-F} in @code{ls}.
|
|
|
848
|
|
|
849 @item colons
|
|
|
850 @samp{-c} in @code{recode}.
|
|
|
851
|
|
|
852 @item command
|
|
|
853 @samp{-c} in @code{su};
|
|
|
854 @samp{-x} in GDB.
|
|
|
855
|
|
|
856 @item compare
|
|
|
857 @samp{-d} in @code{tar}.
|
|
|
858
|
|
|
859 @item compat
|
|
|
860 Used in @code{gawk}.
|
|
|
861
|
|
|
862 @item compress
|
|
|
863 @samp{-Z} in @code{tar} and @code{shar}.
|
|
|
864
|
|
|
865 @item concatenate
|
|
|
866 @samp{-A} in @code{tar}.
|
|
|
867
|
|
|
868 @item confirmation
|
|
|
869 @samp{-w} in @code{tar}.
|
|
|
870
|
|
|
871 @item context
|
|
|
872 Used in @code{diff}.
|
|
|
873
|
|
|
874 @item copyleft
|
|
|
875 @samp{-W copyleft} in @code{gawk}.
|
|
|
876
|
|
|
877 @item copyright
|
|
|
878 @samp{-C} in @code{ptx}, @code{recode}, and @code{wdiff};
|
|
|
879 @samp{-W copyright} in @code{gawk}.
|
|
|
880
|
|
|
881 @item core
|
|
|
882 Used in GDB.
|
|
|
883
|
|
|
884 @item count
|
|
|
885 @samp{-q} in @code{who}.
|
|
|
886
|
|
|
887 @item count-links
|
|
|
888 @samp{-l} in @code{du}.
|
|
|
889
|
|
|
890 @item create
|
|
|
891 Used in @code{tar} and @code{cpio}.
|
|
|
892
|
|
|
893 @item cut-mark
|
|
|
894 @samp{-c} in @code{shar}.
|
|
|
895
|
|
|
896 @item cxref
|
|
|
897 @samp{-x} in @code{ctags}.
|
|
|
898
|
|
|
899 @item date
|
|
|
900 @samp{-d} in @code{touch}.
|
|
|
901
|
|
|
902 @item debug
|
|
|
903 @samp{-d} in Make and @code{m4};
|
|
|
904 @samp{-t} in Bison.
|
|
|
905
|
|
|
906 @item define
|
|
|
907 @samp{-D} in @code{m4}.
|
|
|
908
|
|
|
909 @item defines
|
|
|
910 @samp{-d} in Bison and @code{ctags}.
|
|
|
911
|
|
|
912 @item delete
|
|
|
913 @samp{-D} in @code{tar}.
|
|
|
914
|
|
|
915 @item dereference
|
|
|
916 @samp{-L} in @code{chgrp}, @code{chown}, @code{cpio}, @code{du},
|
|
|
917 @code{ls}, and @code{tar}.
|
|
|
918
|
|
|
919 @item dereference-args
|
|
|
920 @samp{-D} in @code{du}.
|
|
|
921
|
|
|
922 @item device
|
|
|
923 Specify an I/O device (special file name).
|
|
|
924
|
|
|
925 @item diacritics
|
|
|
926 @samp{-d} in @code{recode}.
|
|
|
927
|
|
|
928 @item dictionary-order
|
|
|
929 @samp{-d} in @code{look}.
|
|
|
930
|
|
|
931 @item diff
|
|
|
932 @samp{-d} in @code{tar}.
|
|
|
933
|
|
|
934 @item digits
|
|
|
935 @samp{-n} in @code{csplit}.
|
|
|
936
|
|
|
937 @item directory
|
|
|
938 Specify the directory to use, in various programs. In @code{ls}, it
|
|
|
939 means to show directories themselves rather than their contents. In
|
|
|
940 @code{rm} and @code{ln}, it means to not treat links to directories
|
|
|
941 specially.
|
|
|
942
|
|
|
943 @item discard-all
|
|
|
944 @samp{-x} in @code{strip}.
|
|
|
945
|
|
|
946 @item discard-locals
|
|
|
947 @samp{-X} in @code{strip}.
|
|
|
948
|
|
|
949 @item dry-run
|
|
|
950 @samp{-n} in Make.
|
|
|
951
|
|
|
952 @item ed
|
|
|
953 @samp{-e} in @code{diff}.
|
|
|
954
|
|
|
955 @item elide-empty-files
|
|
|
956 @samp{-z} in @code{csplit}.
|
|
|
957
|
|
|
958 @item end-delete
|
|
|
959 @samp{-x} in @code{wdiff}.
|
|
|
960
|
|
|
961 @item end-insert
|
|
|
962 @samp{-z} in @code{wdiff}.
|
|
|
963
|
|
|
964 @item entire-new-file
|
|
|
965 @samp{-N} in @code{diff}.
|
|
|
966
|
|
|
967 @item environment-overrides
|
|
|
968 @samp{-e} in Make.
|
|
|
969
|
|
|
970 @item eof
|
|
|
971 @samp{-e} in @code{xargs}.
|
|
|
972
|
|
|
973 @item epoch
|
|
|
974 Used in GDB.
|
|
|
975
|
|
|
976 @item error-limit
|
|
|
977 Used in @code{makeinfo}.
|
|
|
978
|
|
|
979 @item error-output
|
|
|
980 @samp{-o} in @code{m4}.
|
|
|
981
|
|
|
982 @item escape
|
|
|
983 @samp{-b} in @code{ls}.
|
|
|
984
|
|
|
985 @item exclude-from
|
|
|
986 @samp{-X} in @code{tar}.
|
|
|
987
|
|
|
988 @item exec
|
|
|
989 Used in GDB.
|
|
|
990
|
|
|
991 @item exit
|
|
|
992 @samp{-x} in @code{xargs}.
|
|
|
993
|
|
|
994 @item exit-0
|
|
|
995 @samp{-e} in @code{unshar}.
|
|
|
996
|
|
|
997 @item expand-tabs
|
|
|
998 @samp{-t} in @code{diff}.
|
|
|
999
|
|
|
1000 @item expression
|
|
|
1001 @samp{-e} in @code{sed}.
|
|
|
1002
|
|
|
1003 @item extern-only
|
|
|
1004 @samp{-g} in @code{nm}.
|
|
|
1005
|
|
|
1006 @item extract
|
|
|
1007 @samp{-i} in @code{cpio};
|
|
|
1008 @samp{-x} in @code{tar}.
|
|
|
1009
|
|
|
1010 @item faces
|
|
|
1011 @samp{-f} in @code{finger}.
|
|
|
1012
|
|
|
1013 @item fast
|
|
|
1014 @samp{-f} in @code{su}.
|
|
|
1015
|
|
|
1016 @item fatal-warnings
|
|
|
1017 @samp{-E} in @code{m4}.
|
|
|
1018
|
|
|
1019 @item file
|
|
|
1020 @samp{-f} in @code{info}, @code{gawk}, Make, @code{mt}, and @code{tar};
|
|
|
1021 @samp{-n} in @code{sed};
|
|
|
1022 @samp{-r} in @code{touch}.
|
|
|
1023
|
|
|
1024 @item field-separator
|
|
|
1025 @samp{-F} in @code{gawk}.
|
|
|
1026
|
|
|
1027 @item file-prefix
|
|
|
1028 @samp{-b} in Bison.
|
|
|
1029
|
|
|
1030 @item file-type
|
|
|
1031 @samp{-F} in @code{ls}.
|
|
|
1032
|
|
|
1033 @item files-from
|
|
|
1034 @samp{-T} in @code{tar}.
|
|
|
1035
|
|
|
1036 @item fill-column
|
|
|
1037 Used in @code{makeinfo}.
|
|
|
1038
|
|
|
1039 @item flag-truncation
|
|
|
1040 @samp{-F} in @code{ptx}.
|
|
|
1041
|
|
|
1042 @item fixed-output-files
|
|
|
1043 @samp{-y} in Bison.
|
|
|
1044
|
|
|
1045 @item follow
|
|
|
1046 @samp{-f} in @code{tail}.
|
|
|
1047
|
|
|
1048 @item footnote-style
|
|
|
1049 Used in @code{makeinfo}.
|
|
|
1050
|
|
|
1051 @item force
|
|
|
1052 @samp{-f} in @code{cp}, @code{ln}, @code{mv}, and @code{rm}.
|
|
|
1053
|
|
|
1054 @item force-prefix
|
|
|
1055 @samp{-F} in @code{shar}.
|
|
|
1056
|
|
|
1057 @item foreground
|
|
|
1058 For server programs, run in the foreground;
|
|
|
1059 in other words, don't do anything special to run the server
|
|
|
1060 in the background.
|
|
|
1061
|
|
|
1062 @item format
|
|
|
1063 Used in @code{ls}, @code{time}, and @code{ptx}.
|
|
|
1064
|
|
|
1065 @item freeze-state
|
|
|
1066 @samp{-F} in @code{m4}.
|
|
|
1067
|
|
|
1068 @item fullname
|
|
|
1069 Used in GDB.
|
|
|
1070
|
|
|
1071 @item gap-size
|
|
|
1072 @samp{-g} in @code{ptx}.
|
|
|
1073
|
|
|
1074 @item get
|
|
|
1075 @samp{-x} in @code{tar}.
|
|
|
1076
|
|
|
1077 @item graphic
|
|
|
1078 @samp{-i} in @code{ul}.
|
|
|
1079
|
|
|
1080 @item graphics
|
|
|
1081 @samp{-g} in @code{recode}.
|
|
|
1082
|
|
|
1083 @item group
|
|
|
1084 @samp{-g} in @code{install}.
|
|
|
1085
|
|
|
1086 @item gzip
|
|
|
1087 @samp{-z} in @code{tar} and @code{shar}.
|
|
|
1088
|
|
|
1089 @item hashsize
|
|
|
1090 @samp{-H} in @code{m4}.
|
|
|
1091
|
|
|
1092 @item header
|
|
|
1093 @samp{-h} in @code{objdump} and @code{recode}
|
|
|
1094
|
|
|
1095 @item heading
|
|
|
1096 @samp{-H} in @code{who}.
|
|
|
1097
|
|
|
1098 @item help
|
|
|
1099 Used to ask for brief usage information.
|
|
|
1100
|
|
|
1101 @item here-delimiter
|
|
|
1102 @samp{-d} in @code{shar}.
|
|
|
1103
|
|
|
1104 @item hide-control-chars
|
|
|
1105 @samp{-q} in @code{ls}.
|
|
|
1106
|
|
|
1107 @item idle
|
|
|
1108 @samp{-u} in @code{who}.
|
|
|
1109
|
|
|
1110 @item ifdef
|
|
|
1111 @samp{-D} in @code{diff}.
|
|
|
1112
|
|
|
1113 @item ignore
|
|
|
1114 @samp{-I} in @code{ls};
|
|
|
1115 @samp{-x} in @code{recode}.
|
|
|
1116
|
|
|
1117 @item ignore-all-space
|
|
|
1118 @samp{-w} in @code{diff}.
|
|
|
1119
|
|
|
1120 @item ignore-backups
|
|
|
1121 @samp{-B} in @code{ls}.
|
|
|
1122
|
|
|
1123 @item ignore-blank-lines
|
|
|
1124 @samp{-B} in @code{diff}.
|
|
|
1125
|
|
|
1126 @item ignore-case
|
|
|
1127 @samp{-f} in @code{look} and @code{ptx};
|
|
|
1128 @samp{-i} in @code{diff} and @code{wdiff}.
|
|
|
1129
|
|
|
1130 @item ignore-errors
|
|
|
1131 @samp{-i} in Make.
|
|
|
1132
|
|
|
1133 @item ignore-file
|
|
|
1134 @samp{-i} in @code{ptx}.
|
|
|
1135
|
|
|
1136 @item ignore-indentation
|
|
|
1137 @samp{-I} in @code{etags}.
|
|
|
1138
|
|
|
1139 @item ignore-init-file
|
|
|
1140 @samp{-f} in Oleo.
|
|
|
1141
|
|
|
1142 @item ignore-interrupts
|
|
|
1143 @samp{-i} in @code{tee}.
|
|
|
1144
|
|
|
1145 @item ignore-matching-lines
|
|
|
1146 @samp{-I} in @code{diff}.
|
|
|
1147
|
|
|
1148 @item ignore-space-change
|
|
|
1149 @samp{-b} in @code{diff}.
|
|
|
1150
|
|
|
1151 @item ignore-zeros
|
|
|
1152 @samp{-i} in @code{tar}.
|
|
|
1153
|
|
|
1154 @item include
|
|
|
1155 @samp{-i} in @code{etags};
|
|
|
1156 @samp{-I} in @code{m4}.
|
|
|
1157
|
|
|
1158 @item include-dir
|
|
|
1159 @samp{-I} in Make.
|
|
|
1160
|
|
|
1161 @item incremental
|
|
|
1162 @samp{-G} in @code{tar}.
|
|
|
1163
|
|
|
1164 @item info
|
|
|
1165 @samp{-i}, @samp{-l}, and @samp{-m} in Finger.
|
|
|
1166
|
|
|
1167 @item initial
|
|
|
1168 @samp{-i} in @code{expand}.
|
|
|
1169
|
|
|
1170 @item initial-tab
|
|
|
1171 @samp{-T} in @code{diff}.
|
|
|
1172
|
|
|
1173 @item inode
|
|
|
1174 @samp{-i} in @code{ls}.
|
|
|
1175
|
|
|
1176 @item interactive
|
|
|
1177 @samp{-i} in @code{cp}, @code{ln}, @code{mv}, @code{rm};
|
|
|
1178 @samp{-e} in @code{m4};
|
|
|
1179 @samp{-p} in @code{xargs};
|
|
|
1180 @samp{-w} in @code{tar}.
|
|
|
1181
|
|
|
1182 @item intermix-type
|
|
|
1183 @samp{-p} in @code{shar}.
|
|
|
1184
|
|
|
1185 @item jobs
|
|
|
1186 @samp{-j} in Make.
|
|
|
1187
|
|
|
1188 @item just-print
|
|
|
1189 @samp{-n} in Make.
|
|
|
1190
|
|
|
1191 @item keep-going
|
|
|
1192 @samp{-k} in Make.
|
|
|
1193
|
|
|
1194 @item keep-files
|
|
|
1195 @samp{-k} in @code{csplit}.
|
|
|
1196
|
|
|
1197 @item kilobytes
|
|
|
1198 @samp{-k} in @code{du} and @code{ls}.
|
|
|
1199
|
|
|
1200 @item language
|
|
|
1201 @samp{-l} in @code{etags}.
|
|
|
1202
|
|
|
1203 @item less-mode
|
|
|
1204 @samp{-l} in @code{wdiff}.
|
|
|
1205
|
|
|
1206 @item level-for-gzip
|
|
|
1207 @samp{-g} in @code{shar}.
|
|
|
1208
|
|
|
1209 @item line-bytes
|
|
|
1210 @samp{-C} in @code{split}.
|
|
|
1211
|
|
|
1212 @item lines
|
|
|
1213 Used in @code{split}, @code{head}, and @code{tail}.
|
|
|
1214
|
|
|
1215 @item link
|
|
|
1216 @samp{-l} in @code{cpio}.
|
|
|
1217
|
|
|
1218 @item lint
|
|
|
1219 @itemx lint-old
|
|
|
1220 Used in @code{gawk}.
|
|
|
1221
|
|
|
1222 @item list
|
|
|
1223 @samp{-t} in @code{cpio};
|
|
|
1224 @samp{-l} in @code{recode}.
|
|
|
1225
|
|
|
1226 @item list
|
|
|
1227 @samp{-t} in @code{tar}.
|
|
|
1228
|
|
|
1229 @item literal
|
|
|
1230 @samp{-N} in @code{ls}.
|
|
|
1231
|
|
|
1232 @item load-average
|
|
|
1233 @samp{-l} in Make.
|
|
|
1234
|
|
|
1235 @item login
|
|
|
1236 Used in @code{su}.
|
|
|
1237
|
|
|
1238 @item machine
|
|
|
1239 No listing of which programs already use this;
|
|
|
1240 someone should check to
|
|
|
1241 see if any actually do, and tell @email{gnu@@gnu.org}.
|
|
|
1242
|
|
|
1243 @item macro-name
|
|
|
1244 @samp{-M} in @code{ptx}.
|
|
|
1245
|
|
|
1246 @item mail
|
|
|
1247 @samp{-m} in @code{hello} and @code{uname}.
|
|
|
1248
|
|
|
1249 @item make-directories
|
|
|
1250 @samp{-d} in @code{cpio}.
|
|
|
1251
|
|
|
1252 @item makefile
|
|
|
1253 @samp{-f} in Make.
|
|
|
1254
|
|
|
1255 @item mapped
|
|
|
1256 Used in GDB.
|
|
|
1257
|
|
|
1258 @item max-args
|
|
|
1259 @samp{-n} in @code{xargs}.
|
|
|
1260
|
|
|
1261 @item max-chars
|
|
|
1262 @samp{-n} in @code{xargs}.
|
|
|
1263
|
|
|
1264 @item max-lines
|
|
|
1265 @samp{-l} in @code{xargs}.
|
|
|
1266
|
|
|
1267 @item max-load
|
|
|
1268 @samp{-l} in Make.
|
|
|
1269
|
|
|
1270 @item max-procs
|
|
|
1271 @samp{-P} in @code{xargs}.
|
|
|
1272
|
|
|
1273 @item mesg
|
|
|
1274 @samp{-T} in @code{who}.
|
|
|
1275
|
|
|
1276 @item message
|
|
|
1277 @samp{-T} in @code{who}.
|
|
|
1278
|
|
|
1279 @item minimal
|
|
|
1280 @samp{-d} in @code{diff}.
|
|
|
1281
|
|
|
1282 @item mixed-uuencode
|
|
|
1283 @samp{-M} in @code{shar}.
|
|
|
1284
|
|
|
1285 @item mode
|
|
|
1286 @samp{-m} in @code{install}, @code{mkdir}, and @code{mkfifo}.
|
|
|
1287
|
|
|
1288 @item modification-time
|
|
|
1289 @samp{-m} in @code{tar}.
|
|
|
1290
|
|
|
1291 @item multi-volume
|
|
|
1292 @samp{-M} in @code{tar}.
|
|
|
1293
|
|
|
1294 @item name-prefix
|
|
|
1295 @samp{-a} in Bison.
|
|
|
1296
|
|
|
1297 @item nesting-limit
|
|
|
1298 @samp{-L} in @code{m4}.
|
|
|
1299
|
|
|
1300 @item net-headers
|
|
|
1301 @samp{-a} in @code{shar}.
|
|
|
1302
|
|
|
1303 @item new-file
|
|
|
1304 @samp{-W} in Make.
|
|
|
1305
|
|
|
1306 @item no-builtin-rules
|
|
|
1307 @samp{-r} in Make.
|
|
|
1308
|
|
|
1309 @item no-character-count
|
|
|
1310 @samp{-w} in @code{shar}.
|
|
|
1311
|
|
|
1312 @item no-check-existing
|
|
|
1313 @samp{-x} in @code{shar}.
|
|
|
1314
|
|
|
1315 @item no-common
|
|
|
1316 @samp{-3} in @code{wdiff}.
|
|
|
1317
|
|
|
1318 @item no-create
|
|
|
1319 @samp{-c} in @code{touch}.
|
|
|
1320
|
|
|
1321 @item no-defines
|
|
|
1322 @samp{-D} in @code{etags}.
|
|
|
1323
|
|
|
1324 @item no-deleted
|
|
|
1325 @samp{-1} in @code{wdiff}.
|
|
|
1326
|
|
|
1327 @item no-dereference
|
|
|
1328 @samp{-d} in @code{cp}.
|
|
|
1329
|
|
|
1330 @item no-inserted
|
|
|
1331 @samp{-2} in @code{wdiff}.
|
|
|
1332
|
|
|
1333 @item no-keep-going
|
|
|
1334 @samp{-S} in Make.
|
|
|
1335
|
|
|
1336 @item no-lines
|
|
|
1337 @samp{-l} in Bison.
|
|
|
1338
|
|
|
1339 @item no-piping
|
|
|
1340 @samp{-P} in @code{shar}.
|
|
|
1341
|
|
|
1342 @item no-prof
|
|
|
1343 @samp{-e} in @code{gprof}.
|
|
|
1344
|
|
|
1345 @item no-regex
|
|
|
1346 @samp{-R} in @code{etags}.
|
|
|
1347
|
|
|
1348 @item no-sort
|
|
|
1349 @samp{-p} in @code{nm}.
|
|
|
1350
|
|
|
1351 @item no-split
|
|
|
1352 Used in @code{makeinfo}.
|
|
|
1353
|
|
|
1354 @item no-static
|
|
|
1355 @samp{-a} in @code{gprof}.
|
|
|
1356
|
|
|
1357 @item no-time
|
|
|
1358 @samp{-E} in @code{gprof}.
|
|
|
1359
|
|
|
1360 @item no-timestamp
|
|
|
1361 @samp{-m} in @code{shar}.
|
|
|
1362
|
|
|
1363 @item no-validate
|
|
|
1364 Used in @code{makeinfo}.
|
|
|
1365
|
|
|
1366 @item no-wait
|
|
|
1367 Used in @code{emacsclient}.
|
|
|
1368
|
|
|
1369 @item no-warn
|
|
|
1370 Used in various programs to inhibit warnings.
|
|
|
1371
|
|
|
1372 @item node
|
|
|
1373 @samp{-n} in @code{info}.
|
|
|
1374
|
|
|
1375 @item nodename
|
|
|
1376 @samp{-n} in @code{uname}.
|
|
|
1377
|
|
|
1378 @item nonmatching
|
|
|
1379 @samp{-f} in @code{cpio}.
|
|
|
1380
|
|
|
1381 @item nstuff
|
|
|
1382 @samp{-n} in @code{objdump}.
|
|
|
1383
|
|
|
1384 @item null
|
|
|
1385 @samp{-0} in @code{xargs}.
|
|
|
1386
|
|
|
1387 @item number
|
|
|
1388 @samp{-n} in @code{cat}.
|
|
|
1389
|
|
|
1390 @item number-nonblank
|
|
|
1391 @samp{-b} in @code{cat}.
|
|
|
1392
|
|
|
1393 @item numeric-sort
|
|
|
1394 @samp{-n} in @code{nm}.
|
|
|
1395
|
|
|
1396 @item numeric-uid-gid
|
|
|
1397 @samp{-n} in @code{cpio} and @code{ls}.
|
|
|
1398
|
|
|
1399 @item nx
|
|
|
1400 Used in GDB.
|
|
|
1401
|
|
|
1402 @item old-archive
|
|
|
1403 @samp{-o} in @code{tar}.
|
|
|
1404
|
|
|
1405 @item old-file
|
|
|
1406 @samp{-o} in Make.
|
|
|
1407
|
|
|
1408 @item one-file-system
|
|
|
1409 @samp{-l} in @code{tar}, @code{cp}, and @code{du}.
|
|
|
1410
|
|
|
1411 @item only-file
|
|
|
1412 @samp{-o} in @code{ptx}.
|
|
|
1413
|
|
|
1414 @item only-prof
|
|
|
1415 @samp{-f} in @code{gprof}.
|
|
|
1416
|
|
|
1417 @item only-time
|
|
|
1418 @samp{-F} in @code{gprof}.
|
|
|
1419
|
|
|
1420 @item options
|
|
|
1421 @samp{-o} in @code{getopt}, @code{fdlist}, @code{fdmount},
|
|
|
1422 @code{fdmountd}, and @code{fdumount}.
|
|
|
1423
|
|
|
1424 @item output
|
|
|
1425 In various programs, specify the output file name.
|
|
|
1426
|
|
|
1427 @item output-prefix
|
|
|
1428 @samp{-o} in @code{shar}.
|
|
|
1429
|
|
|
1430 @item override
|
|
|
1431 @samp{-o} in @code{rm}.
|
|
|
1432
|
|
|
1433 @item overwrite
|
|
|
1434 @samp{-c} in @code{unshar}.
|
|
|
1435
|
|
|
1436 @item owner
|
|
|
1437 @samp{-o} in @code{install}.
|
|
|
1438
|
|
|
1439 @item paginate
|
|
|
1440 @samp{-l} in @code{diff}.
|
|
|
1441
|
|
|
1442 @item paragraph-indent
|
|
|
1443 Used in @code{makeinfo}.
|
|
|
1444
|
|
|
1445 @item parents
|
|
|
1446 @samp{-p} in @code{mkdir} and @code{rmdir}.
|
|
|
1447
|
|
|
1448 @item pass-all
|
|
|
1449 @samp{-p} in @code{ul}.
|
|
|
1450
|
|
|
1451 @item pass-through
|
|
|
1452 @samp{-p} in @code{cpio}.
|
|
|
1453
|
|
|
1454 @item port
|
|
|
1455 @samp{-P} in @code{finger}.
|
|
|
1456
|
|
|
1457 @item portability
|
|
|
1458 @samp{-c} in @code{cpio} and @code{tar}.
|
|
|
1459
|
|
|
1460 @item posix
|
|
|
1461 Used in @code{gawk}.
|
|
|
1462
|
|
|
1463 @item prefix-builtins
|
|
|
1464 @samp{-P} in @code{m4}.
|
|
|
1465
|
|
|
1466 @item prefix
|
|
|
1467 @samp{-f} in @code{csplit}.
|
|
|
1468
|
|
|
1469 @item preserve
|
|
|
1470 Used in @code{tar} and @code{cp}.
|
|
|
1471
|
|
|
1472 @item preserve-environment
|
|
|
1473 @samp{-p} in @code{su}.
|
|
|
1474
|
|
|
1475 @item preserve-modification-time
|
|
|
1476 @samp{-m} in @code{cpio}.
|
|
|
1477
|
|
|
1478 @item preserve-order
|
|
|
1479 @samp{-s} in @code{tar}.
|
|
|
1480
|
|
|
1481 @item preserve-permissions
|
|
|
1482 @samp{-p} in @code{tar}.
|
|
|
1483
|
|
|
1484 @item print
|
|
|
1485 @samp{-l} in @code{diff}.
|
|
|
1486
|
|
|
1487 @item print-chars
|
|
|
1488 @samp{-L} in @code{cmp}.
|
|
|
1489
|
|
|
1490 @item print-data-base
|
|
|
1491 @samp{-p} in Make.
|
|
|
1492
|
|
|
1493 @item print-directory
|
|
|
1494 @samp{-w} in Make.
|
|
|
1495
|
|
|
1496 @item print-file-name
|
|
|
1497 @samp{-o} in @code{nm}.
|
|
|
1498
|
|
|
1499 @item print-symdefs
|
|
|
1500 @samp{-s} in @code{nm}.
|
|
|
1501
|
|
|
1502 @item printer
|
|
|
1503 @samp{-p} in @code{wdiff}.
|
|
|
1504
|
|
|
1505 @item prompt
|
|
|
1506 @samp{-p} in @code{ed}.
|
|
|
1507
|
|
|
1508 @item proxy
|
|
|
1509 Specify an HTTP proxy.
|
|
|
1510
|
|
|
1511 @item query-user
|
|
|
1512 @samp{-X} in @code{shar}.
|
|
|
1513
|
|
|
1514 @item question
|
|
|
1515 @samp{-q} in Make.
|
|
|
1516
|
|
|
1517 @item quiet
|
|
|
1518 Used in many programs to inhibit the usual output. @strong{Note:} every
|
|
|
1519 program accepting @samp{--quiet} should accept @samp{--silent} as a
|
|
|
1520 synonym.
|
|
|
1521
|
|
|
1522 @item quiet-unshar
|
|
|
1523 @samp{-Q} in @code{shar}
|
|
|
1524
|
|
|
1525 @item quote-name
|
|
|
1526 @samp{-Q} in @code{ls}.
|
|
|
1527
|
|
|
1528 @item rcs
|
|
|
1529 @samp{-n} in @code{diff}.
|
|
|
1530
|
|
|
1531 @item re-interval
|
|
|
1532 Used in @code{gawk}.
|
|
|
1533
|
|
|
1534 @item read-full-blocks
|
|
|
1535 @samp{-B} in @code{tar}.
|
|
|
1536
|
|
|
1537 @item readnow
|
|
|
1538 Used in GDB.
|
|
|
1539
|
|
|
1540 @item recon
|
|
|
1541 @samp{-n} in Make.
|
|
|
1542
|
|
|
1543 @item record-number
|
|
|
1544 @samp{-R} in @code{tar}.
|
|
|
1545
|
|
|
1546 @item recursive
|
|
|
1547 Used in @code{chgrp}, @code{chown}, @code{cp}, @code{ls}, @code{diff},
|
|
|
1548 and @code{rm}.
|
|
|
1549
|
|
|
1550 @item reference-limit
|
|
|
1551 Used in @code{makeinfo}.
|
|
|
1552
|
|
|
1553 @item references
|
|
|
1554 @samp{-r} in @code{ptx}.
|
|
|
1555
|
|
|
1556 @item regex
|
|
|
1557 @samp{-r} in @code{tac} and @code{etags}.
|
|
|
1558
|
|
|
1559 @item release
|
|
|
1560 @samp{-r} in @code{uname}.
|
|
|
1561
|
|
|
1562 @item reload-state
|
|
|
1563 @samp{-R} in @code{m4}.
|
|
|
1564
|
|
|
1565 @item relocation
|
|
|
1566 @samp{-r} in @code{objdump}.
|
|
|
1567
|
|
|
1568 @item rename
|
|
|
1569 @samp{-r} in @code{cpio}.
|
|
|
1570
|
|
|
1571 @item replace
|
|
|
1572 @samp{-i} in @code{xargs}.
|
|
|
1573
|
|
|
1574 @item report-identical-files
|
|
|
1575 @samp{-s} in @code{diff}.
|
|
|
1576
|
|
|
1577 @item reset-access-time
|
|
|
1578 @samp{-a} in @code{cpio}.
|
|
|
1579
|
|
|
1580 @item reverse
|
|
|
1581 @samp{-r} in @code{ls} and @code{nm}.
|
|
|
1582
|
|
|
1583 @item reversed-ed
|
|
|
1584 @samp{-f} in @code{diff}.
|
|
|
1585
|
|
|
1586 @item right-side-defs
|
|
|
1587 @samp{-R} in @code{ptx}.
|
|
|
1588
|
|
|
1589 @item same-order
|
|
|
1590 @samp{-s} in @code{tar}.
|
|
|
1591
|
|
|
1592 @item same-permissions
|
|
|
1593 @samp{-p} in @code{tar}.
|
|
|
1594
|
|
|
1595 @item save
|
|
|
1596 @samp{-g} in @code{stty}.
|
|
|
1597
|
|
|
1598 @item se
|
|
|
1599 Used in GDB.
|
|
|
1600
|
|
|
1601 @item sentence-regexp
|
|
|
1602 @samp{-S} in @code{ptx}.
|
|
|
1603
|
|
|
1604 @item separate-dirs
|
|
|
1605 @samp{-S} in @code{du}.
|
|
|
1606
|
|
|
1607 @item separator
|
|
|
1608 @samp{-s} in @code{tac}.
|
|
|
1609
|
|
|
1610 @item sequence
|
|
|
1611 Used by @code{recode} to chose files or pipes for sequencing passes.
|
|
|
1612
|
|
|
1613 @item shell
|
|
|
1614 @samp{-s} in @code{su}.
|
|
|
1615
|
|
|
1616 @item show-all
|
|
|
1617 @samp{-A} in @code{cat}.
|
|
|
1618
|
|
|
1619 @item show-c-function
|
|
|
1620 @samp{-p} in @code{diff}.
|
|
|
1621
|
|
|
1622 @item show-ends
|
|
|
1623 @samp{-E} in @code{cat}.
|
|
|
1624
|
|
|
1625 @item show-function-line
|
|
|
1626 @samp{-F} in @code{diff}.
|
|
|
1627
|
|
|
1628 @item show-tabs
|
|
|
1629 @samp{-T} in @code{cat}.
|
|
|
1630
|
|
|
1631 @item silent
|
|
|
1632 Used in many programs to inhibit the usual output.
|
|
|
1633 @strong{Note:} every program accepting
|
|
|
1634 @samp{--silent} should accept @samp{--quiet} as a synonym.
|
|
|
1635
|
|
|
1636 @item size
|
|
|
1637 @samp{-s} in @code{ls}.
|
|
|
1638
|
|
|
1639 @item socket
|
|
|
1640 Specify a file descriptor for a network server to use for its socket,
|
|
|
1641 instead of opening and binding a new socket. This provides a way to
|
|
|
1642 run, in a nonpriveledged process, a server that normally needs a
|
|
|
1643 reserved port number.
|
|
|
1644
|
|
|
1645 @item sort
|
|
|
1646 Used in @code{ls}.
|
|
|
1647
|
|
|
1648 @item source
|
|
|
1649 @samp{-W source} in @code{gawk}.
|
|
|
1650
|
|
|
1651 @item sparse
|
|
|
1652 @samp{-S} in @code{tar}.
|
|
|
1653
|
|
|
1654 @item speed-large-files
|
|
|
1655 @samp{-H} in @code{diff}.
|
|
|
1656
|
|
|
1657 @item split-at
|
|
|
1658 @samp{-E} in @code{unshar}.
|
|
|
1659
|
|
|
1660 @item split-size-limit
|
|
|
1661 @samp{-L} in @code{shar}.
|
|
|
1662
|
|
|
1663 @item squeeze-blank
|
|
|
1664 @samp{-s} in @code{cat}.
|
|
|
1665
|
|
|
1666 @item start-delete
|
|
|
1667 @samp{-w} in @code{wdiff}.
|
|
|
1668
|
|
|
1669 @item start-insert
|
|
|
1670 @samp{-y} in @code{wdiff}.
|
|
|
1671
|
|
|
1672 @item starting-file
|
|
|
1673 Used in @code{tar} and @code{diff} to specify which file within
|
|
|
1674 a directory to start processing with.
|
|
|
1675
|
|
|
1676 @item statistics
|
|
|
1677 @samp{-s} in @code{wdiff}.
|
|
|
1678
|
|
|
1679 @item stdin-file-list
|
|
|
1680 @samp{-S} in @code{shar}.
|
|
|
1681
|
|
|
1682 @item stop
|
|
|
1683 @samp{-S} in Make.
|
|
|
1684
|
|
|
1685 @item strict
|
|
|
1686 @samp{-s} in @code{recode}.
|
|
|
1687
|
|
|
1688 @item strip
|
|
|
1689 @samp{-s} in @code{install}.
|
|
|
1690
|
|
|
1691 @item strip-all
|
|
|
1692 @samp{-s} in @code{strip}.
|
|
|
1693
|
|
|
1694 @item strip-debug
|
|
|
1695 @samp{-S} in @code{strip}.
|
|
|
1696
|
|
|
1697 @item submitter
|
|
|
1698 @samp{-s} in @code{shar}.
|
|
|
1699
|
|
|
1700 @item suffix
|
|
|
1701 @samp{-S} in @code{cp}, @code{ln}, @code{mv}.
|
|
|
1702
|
|
|
1703 @item suffix-format
|
|
|
1704 @samp{-b} in @code{csplit}.
|
|
|
1705
|
|
|
1706 @item sum
|
|
|
1707 @samp{-s} in @code{gprof}.
|
|
|
1708
|
|
|
1709 @item summarize
|
|
|
1710 @samp{-s} in @code{du}.
|
|
|
1711
|
|
|
1712 @item symbolic
|
|
|
1713 @samp{-s} in @code{ln}.
|
|
|
1714
|
|
|
1715 @item symbols
|
|
|
1716 Used in GDB and @code{objdump}.
|
|
|
1717
|
|
|
1718 @item synclines
|
|
|
1719 @samp{-s} in @code{m4}.
|
|
|
1720
|
|
|
1721 @item sysname
|
|
|
1722 @samp{-s} in @code{uname}.
|
|
|
1723
|
|
|
1724 @item tabs
|
|
|
1725 @samp{-t} in @code{expand} and @code{unexpand}.
|
|
|
1726
|
|
|
1727 @item tabsize
|
|
|
1728 @samp{-T} in @code{ls}.
|
|
|
1729
|
|
|
1730 @item terminal
|
|
|
1731 @samp{-T} in @code{tput} and @code{ul}.
|
|
|
1732 @samp{-t} in @code{wdiff}.
|
|
|
1733
|
|
|
1734 @item text
|
|
|
1735 @samp{-a} in @code{diff}.
|
|
|
1736
|
|
|
1737 @item text-files
|
|
|
1738 @samp{-T} in @code{shar}.
|
|
|
1739
|
|
|
1740 @item time
|
|
|
1741 Used in @code{ls} and @code{touch}.
|
|
|
1742
|
|
|
1743 @item timeout
|
|
|
1744 Specify how long to wait before giving up on some operation.
|
|
|
1745
|
|
|
1746 @item to-stdout
|
|
|
1747 @samp{-O} in @code{tar}.
|
|
|
1748
|
|
|
1749 @item total
|
|
|
1750 @samp{-c} in @code{du}.
|
|
|
1751
|
|
|
1752 @item touch
|
|
|
1753 @samp{-t} in Make, @code{ranlib}, and @code{recode}.
|
|
|
1754
|
|
|
1755 @item trace
|
|
|
1756 @samp{-t} in @code{m4}.
|
|
|
1757
|
|
|
1758 @item traditional
|
|
|
1759 @samp{-t} in @code{hello};
|
|
|
1760 @samp{-W traditional} in @code{gawk};
|
|
|
1761 @samp{-G} in @code{ed}, @code{m4}, and @code{ptx}.
|
|
|
1762
|
|
|
1763 @item tty
|
|
|
1764 Used in GDB.
|
|
|
1765
|
|
|
1766 @item typedefs
|
|
|
1767 @samp{-t} in @code{ctags}.
|
|
|
1768
|
|
|
1769 @item typedefs-and-c++
|
|
|
1770 @samp{-T} in @code{ctags}.
|
|
|
1771
|
|
|
1772 @item typeset-mode
|
|
|
1773 @samp{-t} in @code{ptx}.
|
|
|
1774
|
|
|
1775 @item uncompress
|
|
|
1776 @samp{-z} in @code{tar}.
|
|
|
1777
|
|
|
1778 @item unconditional
|
|
|
1779 @samp{-u} in @code{cpio}.
|
|
|
1780
|
|
|
1781 @item undefine
|
|
|
1782 @samp{-U} in @code{m4}.
|
|
|
1783
|
|
|
1784 @item undefined-only
|
|
|
1785 @samp{-u} in @code{nm}.
|
|
|
1786
|
|
|
1787 @item update
|
|
|
1788 @samp{-u} in @code{cp}, @code{ctags}, @code{mv}, @code{tar}.
|
|
|
1789
|
|
|
1790 @item usage
|
|
|
1791 Used in @code{gawk}; same as @samp{--help}.
|
|
|
1792
|
|
|
1793 @item uuencode
|
|
|
1794 @samp{-B} in @code{shar}.
|
|
|
1795
|
|
|
1796 @item vanilla-operation
|
|
|
1797 @samp{-V} in @code{shar}.
|
|
|
1798
|
|
|
1799 @item verbose
|
|
|
1800 Print more information about progress. Many programs support this.
|
|
|
1801
|
|
|
1802 @item verify
|
|
|
1803 @samp{-W} in @code{tar}.
|
|
|
1804
|
|
|
1805 @item version
|
|
|
1806 Print the version number.
|
|
|
1807
|
|
|
1808 @item version-control
|
|
|
1809 @samp{-V} in @code{cp}, @code{ln}, @code{mv}.
|
|
|
1810
|
|
|
1811 @item vgrind
|
|
|
1812 @samp{-v} in @code{ctags}.
|
|
|
1813
|
|
|
1814 @item volume
|
|
|
1815 @samp{-V} in @code{tar}.
|
|
|
1816
|
|
|
1817 @item what-if
|
|
|
1818 @samp{-W} in Make.
|
|
|
1819
|
|
|
1820 @item whole-size-limit
|
|
|
1821 @samp{-l} in @code{shar}.
|
|
|
1822
|
|
|
1823 @item width
|
|
|
1824 @samp{-w} in @code{ls} and @code{ptx}.
|
|
|
1825
|
|
|
1826 @item word-regexp
|
|
|
1827 @samp{-W} in @code{ptx}.
|
|
|
1828
|
|
|
1829 @item writable
|
|
|
1830 @samp{-T} in @code{who}.
|
|
|
1831
|
|
|
1832 @item zeros
|
|
|
1833 @samp{-z} in @code{gprof}.
|
|
|
1834 @end table
|
|
|
1835
|
|
|
1836 @node Memory Usage
|
|
|
1837 @section Memory Usage
|
|
|
1838
|
|
|
1839 If it typically uses just a few meg of memory, don't bother making any
|
|
|
1840 effort to reduce memory usage. For example, if it is impractical for
|
|
|
1841 other reasons to operate on files more than a few meg long, it is
|
|
|
1842 reasonable to read entire input files into core to operate on them.
|
|
|
1843
|
|
|
1844 However, for programs such as @code{cat} or @code{tail}, that can
|
|
|
1845 usefully operate on very large files, it is important to avoid using a
|
|
|
1846 technique that would artificially limit the size of files it can handle.
|
|
|
1847 If a program works by lines and could be applied to arbitrary
|
|
|
1848 user-supplied input files, it should keep only a line in memory, because
|
|
|
1849 this is not very hard and users will want to be able to operate on input
|
|
|
1850 files that are bigger than will fit in core all at once.
|
|
|
1851
|
|
|
1852 If your program creates complicated data structures, just make them in
|
|
|
1853 core and give a fatal error if @code{malloc} returns zero.
|
|
|
1854
|
|
|
1855 @node Writing C
|
|
|
1856 @chapter Making The Best Use of C
|
|
|
1857
|
|
|
1858 This @value{CHAPTER} provides advice on how best to use the C language
|
|
|
1859 when writing GNU software.
|
|
|
1860
|
|
|
1861 @menu
|
|
|
1862 * Formatting:: Formatting Your Source Code
|
|
|
1863 * Comments:: Commenting Your Work
|
|
|
1864 * Syntactic Conventions:: Clean Use of C Constructs
|
|
|
1865 * Names:: Naming Variables and Functions
|
|
|
1866 * System Portability:: Portability between different operating systems
|
|
|
1867 * CPU Portability:: Supporting the range of CPU types
|
|
|
1868 * System Functions:: Portability and ``standard'' library functions
|
|
|
1869 * Internationalization:: Techniques for internationalization
|
|
|
1870 * Mmap:: How you can safely use @code{mmap}.
|
|
|
1871 @end menu
|
|
|
1872
|
|
|
1873 @node Formatting
|
|
|
1874 @section Formatting Your Source Code
|
|
|
1875
|
|
|
1876 It is important to put the open-brace that starts the body of a C
|
|
|
1877 function in column zero, and avoid putting any other open-brace or
|
|
|
1878 open-parenthesis or open-bracket in column zero. Several tools look
|
|
|
1879 for open-braces in column zero to find the beginnings of C functions.
|
|
|
1880 These tools will not work on code not formatted that way.
|
|
|
1881
|
|
|
1882 It is also important for function definitions to start the name of the
|
|
|
1883 function in column zero. This helps people to search for function
|
|
|
1884 definitions, and may also help certain tools recognize them. Thus,
|
|
|
1885 the proper format is this:
|
|
|
1886
|
|
|
1887 @example
|
|
|
1888 static char *
|
|
|
1889 concat (s1, s2) /* Name starts in column zero here */
|
|
|
1890 char *s1, *s2;
|
|
|
1891 @{ /* Open brace in column zero here */
|
|
|
1892 @dots{}
|
|
|
1893 @}
|
|
|
1894 @end example
|
|
|
1895
|
|
|
1896 @noindent
|
|
|
1897 or, if you want to use @sc{ansi} C, format the definition like this:
|
|
|
1898
|
|
|
1899 @example
|
|
|
1900 static char *
|
|
|
1901 concat (char *s1, char *s2)
|
|
|
1902 @{
|
|
|
1903 @dots{}
|
|
|
1904 @}
|
|
|
1905 @end example
|
|
|
1906
|
|
|
1907 In @sc{ansi} C, if the arguments don't fit nicely on one line,
|
|
|
1908 split it like this:
|
|
|
1909
|
|
|
1910 @example
|
|
|
1911 int
|
|
|
1912 lots_of_args (int an_integer, long a_long, short a_short,
|
|
|
1913 double a_double, float a_float)
|
|
|
1914 @dots{}
|
|
|
1915 @end example
|
|
|
1916
|
|
|
1917 For the body of the function, we prefer code formatted like this:
|
|
|
1918
|
|
|
1919 @example
|
|
|
1920 if (x < foo (y, z))
|
|
|
1921 haha = bar[4] + 5;
|
|
|
1922 else
|
|
|
1923 @{
|
|
|
1924 while (z)
|
|
|
1925 @{
|
|
|
1926 haha += foo (z, z);
|
|
|
1927 z--;
|
|
|
1928 @}
|
|
|
1929 return ++x + bar ();
|
|
|
1930 @}
|
|
|
1931 @end example
|
|
|
1932
|
|
|
1933 We find it easier to read a program when it has spaces before the
|
|
|
1934 open-parentheses and after the commas. Especially after the commas.
|
|
|
1935
|
|
|
1936 When you split an expression into multiple lines, split it
|
|
|
1937 before an operator, not after one. Here is the right way:
|
|
|
1938
|
|
|
1939 @example
|
|
|
1940 if (foo_this_is_long && bar > win (x, y, z)
|
|
|
1941 && remaining_condition)
|
|
|
1942 @end example
|
|
|
1943
|
|
|
1944 Try to avoid having two operators of different precedence at the same
|
|
|
1945 level of indentation. For example, don't write this:
|
|
|
1946
|
|
|
1947 @example
|
|
|
1948 mode = (inmode[j] == VOIDmode
|
|
|
1949 || GET_MODE_SIZE (outmode[j]) > GET_MODE_SIZE (inmode[j])
|
|
|
1950 ? outmode[j] : inmode[j]);
|
|
|
1951 @end example
|
|
|
1952
|
|
|
1953 Instead, use extra parentheses so that the indentation shows the nesting:
|
|
|
1954
|
|
|
1955 @example
|
|
|
1956 mode = ((inmode[j] == VOIDmode
|
|
|
1957 || (GET_MODE_SIZE (outmode[j]) > GET_MODE_SIZE (inmode[j])))
|
|
|
1958 ? outmode[j] : inmode[j]);
|
|
|
1959 @end example
|
|
|
1960
|
|
|
1961 Insert extra parentheses so that Emacs will indent the code properly.
|
|
|
1962 For example, the following indentation looks nice if you do it by hand,
|
|
|
1963 but Emacs would mess it up:
|
|
|
1964
|
|
|
1965 @example
|
|
|
1966 v = rup->ru_utime.tv_sec*1000 + rup->ru_utime.tv_usec/1000
|
|
|
1967 + rup->ru_stime.tv_sec*1000 + rup->ru_stime.tv_usec/1000;
|
|
|
1968 @end example
|
|
|
1969
|
|
|
1970 But adding a set of parentheses solves the problem:
|
|
|
1971
|
|
|
1972 @example
|
|
|
1973 v = (rup->ru_utime.tv_sec*1000 + rup->ru_utime.tv_usec/1000
|
|
|
1974 + rup->ru_stime.tv_sec*1000 + rup->ru_stime.tv_usec/1000);
|
|
|
1975 @end example
|
|
|
1976
|
|
|
1977 Format do-while statements like this:
|
|
|
1978
|
|
|
1979 @example
|
|
|
1980 do
|
|
|
1981 @{
|
|
|
1982 a = foo (a);
|
|
|
1983 @}
|
|
|
1984 while (a > 0);
|
|
|
1985 @end example
|
|
|
1986
|
|
|
1987 Please use formfeed characters (control-L) to divide the program into
|
|
|
1988 pages at logical places (but not within a function). It does not matter
|
|
|
1989 just how long the pages are, since they do not have to fit on a printed
|
|
|
1990 page. The formfeeds should appear alone on lines by themselves.
|
|
|
1991
|
|
|
1992
|
|
|
1993 @node Comments
|
|
|
1994 @section Commenting Your Work
|
|
|
1995
|
|
|
1996 Every program should start with a comment saying briefly what it is for.
|
|
|
1997 Example: @samp{fmt - filter for simple filling of text}.
|
|
|
1998
|
|
|
1999 Please write the comments in a GNU program in English, because English
|
|
|
2000 is the one language that nearly all programmers in all countries can
|
|
|
2001 read. If you do not write English well, please write comments in
|
|
|
2002 English as well as you can, then ask other people to help rewrite them.
|
|
|
2003 If you can't write comments in English, please find someone to work with
|
|
|
2004 you and translate your comments into English.
|
|
|
2005
|
|
|
2006 Please put a comment on each function saying what the function does,
|
|
|
2007 what sorts of arguments it gets, and what the possible values of
|
|
|
2008 arguments mean and are used for. It is not necessary to duplicate in
|
|
|
2009 words the meaning of the C argument declarations, if a C type is being
|
|
|
2010 used in its customary fashion. If there is anything nonstandard about
|
|
|
2011 its use (such as an argument of type @code{char *} which is really the
|
|
|
2012 address of the second character of a string, not the first), or any
|
|
|
2013 possible values that would not work the way one would expect (such as,
|
|
|
2014 that strings containing newlines are not guaranteed to work), be sure
|
|
|
2015 to say so.
|
|
|
2016
|
|
|
2017 Also explain the significance of the return value, if there is one.
|
|
|
2018
|
|
|
2019 Please put two spaces after the end of a sentence in your comments, so
|
|
|
2020 that the Emacs sentence commands will work. Also, please write
|
|
|
2021 complete sentences and capitalize the first word. If a lower-case
|
|
|
2022 identifier comes at the beginning of a sentence, don't capitalize it!
|
|
|
2023 Changing the spelling makes it a different identifier. If you don't
|
|
|
2024 like starting a sentence with a lower case letter, write the sentence
|
|
|
2025 differently (e.g., ``The identifier lower-case is @dots{}'').
|
|
|
2026
|
|
|
2027 The comment on a function is much clearer if you use the argument
|
|
|
2028 names to speak about the argument values. The variable name itself
|
|
|
2029 should be lower case, but write it in upper case when you are speaking
|
|
|
2030 about the value rather than the variable itself. Thus, ``the inode
|
|
|
2031 number NODE_NUM'' rather than ``an inode''.
|
|
|
2032
|
|
|
2033 There is usually no purpose in restating the name of the function in
|
|
|
2034 the comment before it, because the reader can see that for himself.
|
|
|
2035 There might be an exception when the comment is so long that the function
|
|
|
2036 itself would be off the bottom of the screen.
|
|
|
2037
|
|
|
2038 There should be a comment on each static variable as well, like this:
|
|
|
2039
|
|
|
2040 @example
|
|
|
2041 /* Nonzero means truncate lines in the display;
|
|
|
2042 zero means continue them. */
|
|
|
2043 int truncate_lines;
|
|
|
2044 @end example
|
|
|
2045
|
|
|
2046 Every @samp{#endif} should have a comment, except in the case of short
|
|
|
2047 conditionals (just a few lines) that are not nested. The comment should
|
|
|
2048 state the condition of the conditional that is ending, @emph{including
|
|
|
2049 its sense}. @samp{#else} should have a comment describing the condition
|
|
|
2050 @emph{and sense} of the code that follows. For example:
|
|
|
2051
|
|
|
2052 @example
|
|
|
2053 @group
|
|
|
2054 #ifdef foo
|
|
|
2055 @dots{}
|
|
|
2056 #else /* not foo */
|
|
|
2057 @dots{}
|
|
|
2058 #endif /* not foo */
|
|
|
2059 @end group
|
|
|
2060 @group
|
|
|
2061 #ifdef foo
|
|
|
2062 @dots{}
|
|
|
2063 #endif /* foo */
|
|
|
2064 @end group
|
|
|
2065 @end example
|
|
|
2066
|
|
|
2067 @noindent
|
|
|
2068 but, by contrast, write the comments this way for a @samp{#ifndef}:
|
|
|
2069
|
|
|
2070 @example
|
|
|
2071 @group
|
|
|
2072 #ifndef foo
|
|
|
2073 @dots{}
|
|
|
2074 #else /* foo */
|
|
|
2075 @dots{}
|
|
|
2076 #endif /* foo */
|
|
|
2077 @end group
|
|
|
2078 @group
|
|
|
2079 #ifndef foo
|
|
|
2080 @dots{}
|
|
|
2081 #endif /* not foo */
|
|
|
2082 @end group
|
|
|
2083 @end example
|
|
|
2084
|
|
|
2085 @node Syntactic Conventions
|
|
|
2086 @section Clean Use of C Constructs
|
|
|
2087
|
|
|
2088 Please explicitly declare all arguments to functions.
|
|
|
2089 Don't omit them just because they are @code{int}s.
|
|
|
2090
|
|
|
2091 Declarations of external functions and functions to appear later in the
|
|
|
2092 source file should all go in one place near the beginning of the file
|
|
|
2093 (somewhere before the first function definition in the file), or else
|
|
|
2094 should go in a header file. Don't put @code{extern} declarations inside
|
|
|
2095 functions.
|
|
|
2096
|
|
|
2097 It used to be common practice to use the same local variables (with
|
|
|
2098 names like @code{tem}) over and over for different values within one
|
|
|
2099 function. Instead of doing this, it is better declare a separate local
|
|
|
2100 variable for each distinct purpose, and give it a name which is
|
|
|
2101 meaningful. This not only makes programs easier to understand, it also
|
|
|
2102 facilitates optimization by good compilers. You can also move the
|
|
|
2103 declaration of each local variable into the smallest scope that includes
|
|
|
2104 all its uses. This makes the program even cleaner.
|
|
|
2105
|
|
|
2106 Don't use local variables or parameters that shadow global identifiers.
|
|
|
2107
|
|
|
2108 Don't declare multiple variables in one declaration that spans lines.
|
|
|
2109 Start a new declaration on each line, instead. For example, instead
|
|
|
2110 of this:
|
|
|
2111
|
|
|
2112 @example
|
|
|
2113 @group
|
|
|
2114 int foo,
|
|
|
2115 bar;
|
|
|
2116 @end group
|
|
|
2117 @end example
|
|
|
2118
|
|
|
2119 @noindent
|
|
|
2120 write either this:
|
|
|
2121
|
|
|
2122 @example
|
|
|
2123 int foo, bar;
|
|
|
2124 @end example
|
|
|
2125
|
|
|
2126 @noindent
|
|
|
2127 or this:
|
|
|
2128
|
|
|
2129 @example
|
|
|
2130 int foo;
|
|
|
2131 int bar;
|
|
|
2132 @end example
|
|
|
2133
|
|
|
2134 @noindent
|
|
|
2135 (If they are global variables, each should have a comment preceding it
|
|
|
2136 anyway.)
|
|
|
2137
|
|
|
2138 When you have an @code{if}-@code{else} statement nested in another
|
|
|
2139 @code{if} statement, always put braces around the @code{if}-@code{else}.
|
|
|
2140 Thus, never write like this:
|
|
|
2141
|
|
|
2142 @example
|
|
|
2143 if (foo)
|
|
|
2144 if (bar)
|
|
|
2145 win ();
|
|
|
2146 else
|
|
|
2147 lose ();
|
|
|
2148 @end example
|
|
|
2149
|
|
|
2150 @noindent
|
|
|
2151 always like this:
|
|
|
2152
|
|
|
2153 @example
|
|
|
2154 if (foo)
|
|
|
2155 @{
|
|
|
2156 if (bar)
|
|
|
2157 win ();
|
|
|
2158 else
|
|
|
2159 lose ();
|
|
|
2160 @}
|
|
|
2161 @end example
|
|
|
2162
|
|
|
2163 If you have an @code{if} statement nested inside of an @code{else}
|
|
|
2164 statement, either write @code{else if} on one line, like this,
|
|
|
2165
|
|
|
2166 @example
|
|
|
2167 if (foo)
|
|
|
2168 @dots{}
|
|
|
2169 else if (bar)
|
|
|
2170 @dots{}
|
|
|
2171 @end example
|
|
|
2172
|
|
|
2173 @noindent
|
|
|
2174 with its @code{then}-part indented like the preceding @code{then}-part,
|
|
|
2175 or write the nested @code{if} within braces like this:
|
|
|
2176
|
|
|
2177 @example
|
|
|
2178 if (foo)
|
|
|
2179 @dots{}
|
|
|
2180 else
|
|
|
2181 @{
|
|
|
2182 if (bar)
|
|
|
2183 @dots{}
|
|
|
2184 @}
|
|
|
2185 @end example
|
|
|
2186
|
|
|
2187 Don't declare both a structure tag and variables or typedefs in the
|
|
|
2188 same declaration. Instead, declare the structure tag separately
|
|
|
2189 and then use it to declare the variables or typedefs.
|
|
|
2190
|
|
|
2191 Try to avoid assignments inside @code{if}-conditions. For example,
|
|
|
2192 don't write this:
|
|
|
2193
|
|
|
2194 @example
|
|
|
2195 if ((foo = (char *) malloc (sizeof *foo)) == 0)
|
|
|
2196 fatal ("virtual memory exhausted");
|
|
|
2197 @end example
|
|
|
2198
|
|
|
2199 @noindent
|
|
|
2200 instead, write this:
|
|
|
2201
|
|
|
2202 @example
|
|
|
2203 foo = (char *) malloc (sizeof *foo);
|
|
|
2204 if (foo == 0)
|
|
|
2205 fatal ("virtual memory exhausted");
|
|
|
2206 @end example
|
|
|
2207
|
|
|
2208 Don't make the program ugly to placate @code{lint}. Please don't insert any
|
|
|
2209 casts to @code{void}. Zero without a cast is perfectly fine as a null
|
|
|
2210 pointer constant, except when calling a varargs function.
|
|
|
2211
|
|
|
2212 @node Names
|
|
|
2213 @section Naming Variables and Functions
|
|
|
2214
|
|
|
2215 The names of global variables and functions in a program serve as
|
|
|
2216 comments of a sort. So don't choose terse names---instead, look for
|
|
|
2217 names that give useful information about the meaning of the variable or
|
|
|
2218 function. In a GNU program, names should be English, like other
|
|
|
2219 comments.
|
|
|
2220
|
|
|
2221 Local variable names can be shorter, because they are used only within
|
|
|
2222 one context, where (presumably) comments explain their purpose.
|
|
|
2223
|
|
|
2224 Try to limit your use of abbreviations in symbol names. It is ok to
|
|
|
2225 make a few abbreviations, explain what they mean, and then use them
|
|
|
2226 frequently, but don't use lots of obscure abbreviations.
|
|
|
2227
|
|
|
2228 Please use underscores to separate words in a name, so that the Emacs
|
|
|
2229 word commands can be useful within them. Stick to lower case; reserve
|
|
|
2230 upper case for macros and @code{enum} constants, and for name-prefixes
|
|
|
2231 that follow a uniform convention.
|
|
|
2232
|
|
|
2233 For example, you should use names like @code{ignore_space_change_flag};
|
|
|
2234 don't use names like @code{iCantReadThis}.
|
|
|
2235
|
|
|
2236 Variables that indicate whether command-line options have been
|
|
|
2237 specified should be named after the meaning of the option, not after
|
|
|
2238 the option-letter. A comment should state both the exact meaning of
|
|
|
2239 the option and its letter. For example,
|
|
|
2240
|
|
|
2241 @example
|
|
|
2242 @group
|
|
|
2243 /* Ignore changes in horizontal whitespace (-b). */
|
|
|
2244 int ignore_space_change_flag;
|
|
|
2245 @end group
|
|
|
2246 @end example
|
|
|
2247
|
|
|
2248 When you want to define names with constant integer values, use
|
|
|
2249 @code{enum} rather than @samp{#define}. GDB knows about enumeration
|
|
|
2250 constants.
|
|
|
2251
|
|
|
2252 Use file names of 14 characters or less, to avoid creating gratuitous
|
|
|
2253 problems on older System V systems. You can use the program
|
|
|
2254 @code{doschk} to test for this. @code{doschk} also tests for potential
|
|
|
2255 name conflicts if the files were loaded onto an MS-DOS file
|
|
|
2256 system---something you may or may not care about.
|
|
|
2257
|
|
|
2258 @node System Portability
|
|
|
2259 @section Portability between System Types
|
|
|
2260
|
|
|
2261 In the Unix world, ``portability'' refers to porting to different Unix
|
|
|
2262 versions. For a GNU program, this kind of portability is desirable, but
|
|
|
2263 not paramount.
|
|
|
2264
|
|
|
2265 The primary purpose of GNU software is to run on top of the GNU kernel,
|
|
|
2266 compiled with the GNU C compiler, on various types of @sc{cpu}. The
|
|
|
2267 amount and kinds of variation among GNU systems on different @sc{cpu}s
|
|
|
2268 will be comparable to the variation among Linux-based GNU systems or
|
|
|
2269 among BSD systems today. So the kinds of portability that are absolutely
|
|
|
2270 necessary are quite limited.
|
|
|
2271
|
|
|
2272 But many users do run GNU software on non-GNU Unix or Unix-like systems.
|
|
|
2273 So supporting a variety of Unix-like systems is desirable, although not
|
|
|
2274 paramount.
|
|
|
2275
|
|
|
2276 The easiest way to achieve portability to most Unix-like systems is to
|
|
|
2277 use Autoconf. It's unlikely that your program needs to know more
|
|
|
2278 information about the host platform than Autoconf can provide, simply
|
|
|
2279 because most of the programs that need such knowledge have already been
|
|
|
2280 written.
|
|
|
2281
|
|
|
2282 Avoid using the format of semi-internal data bases (e.g., directories)
|
|
|
2283 when there is a higher-level alternative (@code{readdir}).
|
|
|
2284
|
|
|
2285 As for systems that are not like Unix, such as MSDOS, Windows, the
|
|
|
2286 Macintosh, VMS, and MVS, supporting them is often a lot of work. When
|
|
|
2287 that is the case, it is better to spend your time adding features that
|
|
|
2288 will be useful on GNU and GNU/Linux, rather than on supporting other
|
|
|
2289 incompatible systems.
|
|
|
2290
|
|
|
2291 @node CPU Portability
|
|
|
2292 @section Portability between @sc{cpu}s
|
|
|
2293
|
|
|
2294 Even GNU systems will differ because of differences among @sc{cpu}
|
|
|
2295 types---for example, difference in byte ordering and alignment
|
|
|
2296 requirements. It is absolutely essential to handle these differences.
|
|
|
2297 However, don't make any effort to cater to the possibility that an
|
|
|
2298 @code{int} will be less than 32 bits. We don't support 16-bit machines
|
|
|
2299 in GNU.
|
|
|
2300
|
|
|
2301 Don't assume that the address of an @code{int} object is also the
|
|
|
2302 address of its least-significant byte. This is false on big-endian
|
|
|
2303 machines. Thus, don't make the following mistake:
|
|
|
2304
|
|
|
2305 @example
|
|
|
2306 int c;
|
|
|
2307 @dots{}
|
|
|
2308 while ((c = getchar()) != EOF)
|
|
|
2309 write(file_descriptor, &c, 1);
|
|
|
2310 @end example
|
|
|
2311
|
|
|
2312 When calling functions, you need not worry about the difference between
|
|
|
2313 pointers of various types, or between pointers and integers. On most
|
|
|
2314 machines, there's no difference anyway. As for the few machines where
|
|
|
2315 there is a difference, all of them support @sc{ansi} C, so you can use
|
|
|
2316 prototypes (conditionalized to be active only in @sc{ansi} C) to make
|
|
|
2317 the code work on those systems.
|
|
|
2318
|
|
|
2319 In certain cases, it is ok to pass integer and pointer arguments
|
|
|
2320 indiscriminately to the same function, and use no prototype on any
|
|
|
2321 system. For example, many GNU programs have error-reporting functions
|
|
|
2322 that pass their arguments along to @code{printf} and friends:
|
|
|
2323
|
|
|
2324 @example
|
|
|
2325 error (s, a1, a2, a3)
|
|
|
2326 char *s;
|
|
|
2327 char *a1, *a2, *a3;
|
|
|
2328 @{
|
|
|
2329 fprintf (stderr, "error: ");
|
|
|
2330 fprintf (stderr, s, a1, a2, a3);
|
|
|
2331 @}
|
|
|
2332 @end example
|
|
|
2333
|
|
|
2334 @noindent
|
|
|
2335 In practice, this works on all machines, since a pointer is generally
|
|
|
2336 the widest possible kind of argument, and it is much simpler than any
|
|
|
2337 ``correct'' alternative. Be sure @emph{not} to use a prototype for such
|
|
|
2338 functions.
|
|
|
2339
|
|
|
2340 However, avoid casting pointers to integers unless you really need to.
|
|
|
2341 Outside of special situations, such casts greatly reduce portability,
|
|
|
2342 and in most programs they are easy to avoid. In the cases where casting
|
|
|
2343 pointers to integers is essential---such as, a Lisp interpreter which
|
|
|
2344 stores type information as well as an address in one word---it is ok to
|
|
|
2345 do it, but you'll have to make explicit provisions to handle different
|
|
|
2346 word sizes.
|
|
|
2347
|
|
|
2348 @node System Functions
|
|
|
2349 @section Calling System Functions
|
|
|
2350
|
|
|
2351 C implementations differ substantially. @sc{ansi} C reduces but does not
|
|
|
2352 eliminate the incompatibilities; meanwhile, many users wish to compile
|
|
|
2353 GNU software with pre-@sc{ansi} compilers. This chapter gives
|
|
|
2354 recommendations for how to use the more or less standard C library
|
|
|
2355 functions to avoid unnecessary loss of portability.
|
|
|
2356
|
|
|
2357 @itemize @bullet
|
|
|
2358 @item
|
|
|
2359 Don't use the value of @code{sprintf}. It returns the number of
|
|
|
2360 characters written on some systems, but not on all systems.
|
|
|
2361
|
|
|
2362 @item
|
|
|
2363 @code{main} should be declared to return type @code{int}. It should
|
|
|
2364 terminate either by calling @code{exit} or by returning the integer
|
|
|
2365 status code; make sure it cannot ever return an undefined value.
|
|
|
2366
|
|
|
2367 @item
|
|
|
2368 Don't declare system functions explicitly.
|
|
|
2369
|
|
|
2370 Almost any declaration for a system function is wrong on some system.
|
|
|
2371 To minimize conflicts, leave it to the system header files to declare
|
|
|
2372 system functions. If the headers don't declare a function, let it
|
|
|
2373 remain undeclared.
|
|
|
2374
|
|
|
2375 While it may seem unclean to use a function without declaring it, in
|
|
|
2376 practice this works fine for most system library functions on the
|
|
|
2377 systems where this really happens; thus, the disadvantage is only
|
|
|
2378 theoretical. By contrast, actual declarations have frequently caused
|
|
|
2379 actual conflicts.
|
|
|
2380
|
|
|
2381 @item
|
|
|
2382 If you must declare a system function, don't specify the argument types.
|
|
|
2383 Use an old-style declaration, not an @sc{ansi} prototype. The more you
|
|
|
2384 specify about the function, the more likely a conflict.
|
|
|
2385
|
|
|
2386 @item
|
|
|
2387 In particular, don't unconditionally declare @code{malloc} or
|
|
|
2388 @code{realloc}.
|
|
|
2389
|
|
|
2390 Most GNU programs use those functions just once, in functions
|
|
|
2391 conventionally named @code{xmalloc} and @code{xrealloc}. These
|
|
|
2392 functions call @code{malloc} and @code{realloc}, respectively, and
|
|
|
2393 check the results.
|
|
|
2394
|
|
|
2395 Because @code{xmalloc} and @code{xrealloc} are defined in your program,
|
|
|
2396 you can declare them in other files without any risk of type conflict.
|
|
|
2397
|
|
|
2398 On most systems, @code{int} is the same length as a pointer; thus, the
|
|
|
2399 calls to @code{malloc} and @code{realloc} work fine. For the few
|
|
|
2400 exceptional systems (mostly 64-bit machines), you can use
|
|
|
2401 @strong{conditionalized} declarations of @code{malloc} and
|
|
|
2402 @code{realloc}---or put these declarations in configuration files
|
|
|
2403 specific to those systems.
|
|
|
2404
|
|
|
2405 @item
|
|
|
2406 The string functions require special treatment. Some Unix systems have
|
|
|
2407 a header file @file{string.h}; others have @file{strings.h}. Neither
|
|
|
2408 file name is portable. There are two things you can do: use Autoconf to
|
|
|
2409 figure out which file to include, or don't include either file.
|
|
|
2410
|
|
|
2411 @item
|
|
|
2412 If you don't include either strings file, you can't get declarations for
|
|
|
2413 the string functions from the header file in the usual way.
|
|
|
2414
|
|
|
2415 That causes less of a problem than you might think. The newer @sc{ansi}
|
|
|
2416 string functions should be avoided anyway because many systems still
|
|
|
2417 don't support them. The string functions you can use are these:
|
|
|
2418
|
|
|
2419 @example
|
|
|
2420 strcpy strncpy strcat strncat
|
|
|
2421 strlen strcmp strncmp
|
|
|
2422 strchr strrchr
|
|
|
2423 @end example
|
|
|
2424
|
|
|
2425 The copy and concatenate functions work fine without a declaration as
|
|
|
2426 long as you don't use their values. Using their values without a
|
|
|
2427 declaration fails on systems where the width of a pointer differs from
|
|
|
2428 the width of @code{int}, and perhaps in other cases. It is trivial to
|
|
|
2429 avoid using their values, so do that.
|
|
|
2430
|
|
|
2431 The compare functions and @code{strlen} work fine without a declaration
|
|
|
2432 on most systems, possibly all the ones that GNU software runs on.
|
|
|
2433 You may find it necessary to declare them @strong{conditionally} on a
|
|
|
2434 few systems.
|
|
|
2435
|
|
|
2436 The search functions must be declared to return @code{char *}. Luckily,
|
|
|
2437 there is no variation in the data type they return. But there is
|
|
|
2438 variation in their names. Some systems give these functions the names
|
|
|
2439 @code{index} and @code{rindex}; other systems use the names
|
|
|
2440 @code{strchr} and @code{strrchr}. Some systems support both pairs of
|
|
|
2441 names, but neither pair works on all systems.
|
|
|
2442
|
|
|
2443 You should pick a single pair of names and use it throughout your
|
|
|
2444 program. (Nowadays, it is better to choose @code{strchr} and
|
|
|
2445 @code{strrchr} for new programs, since those are the standard @sc{ansi}
|
|
|
2446 names.) Declare both of those names as functions returning @code{char
|
|
|
2447 *}. On systems which don't support those names, define them as macros
|
|
|
2448 in terms of the other pair. For example, here is what to put at the
|
|
|
2449 beginning of your file (or in a header) if you want to use the names
|
|
|
2450 @code{strchr} and @code{strrchr} throughout:
|
|
|
2451
|
|
|
2452 @example
|
|
|
2453 #ifndef HAVE_STRCHR
|
|
|
2454 #define strchr index
|
|
|
2455 #endif
|
|
|
2456 #ifndef HAVE_STRRCHR
|
|
|
2457 #define strrchr rindex
|
|
|
2458 #endif
|
|
|
2459
|
|
|
2460 char *strchr ();
|
|
|
2461 char *strrchr ();
|
|
|
2462 @end example
|
|
|
2463 @end itemize
|
|
|
2464
|
|
|
2465 Here we assume that @code{HAVE_STRCHR} and @code{HAVE_STRRCHR} are
|
|
|
2466 macros defined in systems where the corresponding functions exist.
|
|
|
2467 One way to get them properly defined is to use Autoconf.
|
|
|
2468
|
|
|
2469 @node Internationalization
|
|
|
2470 @section Internationalization
|
|
|
2471
|
|
|
2472 GNU has a library called GNU gettext that makes it easy to translate the
|
|
|
2473 messages in a program into various languages. You should use this
|
|
|
2474 library in every program. Use English for the messages as they appear
|
|
|
2475 in the program, and let gettext provide the way to translate them into
|
|
|
2476 other languages.
|
|
|
2477
|
|
|
2478 Using GNU gettext involves putting a call to the @code{gettext} macro
|
|
|
2479 around each string that might need translation---like this:
|
|
|
2480
|
|
|
2481 @example
|
|
|
2482 printf (gettext ("Processing file `%s'..."));
|
|
|
2483 @end example
|
|
|
2484
|
|
|
2485 @noindent
|
|
|
2486 This permits GNU gettext to replace the string @code{"Processing file
|
|
|
2487 `%s'..."} with a translated version.
|
|
|
2488
|
|
|
2489 Once a program uses gettext, please make a point of writing calls to
|
|
|
2490 @code{gettext} when you add new strings that call for translation.
|
|
|
2491
|
|
|
2492 Using GNU gettext in a package involves specifying a @dfn{text domain
|
|
|
2493 name} for the package. The text domain name is used to separate the
|
|
|
2494 translations for this package from the translations for other packages.
|
|
|
2495 Normally, the text domain name should be the same as the name of the
|
|
|
2496 package---for example, @samp{fileutils} for the GNU file utilities.
|
|
|
2497
|
|
|
2498 To enable gettext to work well, avoid writing code that makes
|
|
|
2499 assumptions about the structure of words or sentences. When you want
|
|
|
2500 the precise text of a sentence to vary depending on the data, use two or
|
|
|
2501 more alternative string constants each containing a complete sentences,
|
|
|
2502 rather than inserting conditionalized words or phrases into a single
|
|
|
2503 sentence framework.
|
|
|
2504
|
|
|
2505 Here is an example of what not to do:
|
|
|
2506
|
|
|
2507 @example
|
|
|
2508 printf ("%d file%s processed", nfiles,
|
|
|
2509 nfiles != 1 ? "s" : "");
|
|
|
2510 @end example
|
|
|
2511
|
|
|
2512 @noindent
|
|
|
2513 The problem with that example is that it assumes that plurals are made
|
|
|
2514 by adding `s'. If you apply gettext to the format string, like this,
|
|
|
2515
|
|
|
2516 @example
|
|
|
2517 printf (gettext ("%d file%s processed"), nfiles,
|
|
|
2518 nfiles != 1 ? "s" : "");
|
|
|
2519 @end example
|
|
|
2520
|
|
|
2521 @noindent
|
|
|
2522 the message can use different words, but it will still be forced to use
|
|
|
2523 `s' for the plural. Here is a better way:
|
|
|
2524
|
|
|
2525 @example
|
|
|
2526 printf ((nfiles != 1 ? "%d files processed"
|
|
|
2527 : "%d file processed"),
|
|
|
2528 nfiles);
|
|
|
2529 @end example
|
|
|
2530
|
|
|
2531 @noindent
|
|
|
2532 This way, you can apply gettext to each of the two strings
|
|
|
2533 independently:
|
|
|
2534
|
|
|
2535 @example
|
|
|
2536 printf ((nfiles != 1 ? gettext ("%d files processed")
|
|
|
2537 : gettext ("%d file processed")),
|
|
|
2538 nfiles);
|
|
|
2539 @end example
|
|
|
2540
|
|
|
2541 @noindent
|
|
|
2542 This can be any method of forming the plural of the word for ``file'', and
|
|
|
2543 also handles languages that require agreement in the word for
|
|
|
2544 ``processed''.
|
|
|
2545
|
|
|
2546 A similar problem appears at the level of sentence structure with this
|
|
|
2547 code:
|
|
|
2548
|
|
|
2549 @example
|
|
|
2550 printf ("# Implicit rule search has%s been done.\n",
|
|
|
2551 f->tried_implicit ? "" : " not");
|
|
|
2552 @end example
|
|
|
2553
|
|
|
2554 @noindent
|
|
|
2555 Adding @code{gettext} calls to this code cannot give correct results for
|
|
|
2556 all languages, because negation in some languages requires adding words
|
|
|
2557 at more than one place in the sentence. By contrast, adding
|
|
|
2558 @code{gettext} calls does the job straightfowardly if the code starts
|
|
|
2559 out like this:
|
|
|
2560
|
|
|
2561 @example
|
|
|
2562 printf (f->tried_implicit
|
|
|
2563 ? "# Implicit rule search has been done.\n",
|
|
|
2564 : "# Implicit rule search has not been done.\n");
|
|
|
2565 @end example
|
|
|
2566
|
|
|
2567 @node Mmap
|
|
|
2568 @section Mmap
|
|
|
2569
|
|
|
2570 Don't assume that @code{mmap} either works on all files or fails
|
|
|
2571 for all files. It may work on some files and fail on others.
|
|
|
2572
|
|
|
2573 The proper way to use @code{mmap} is to try it on the specific file for
|
|
|
2574 which you want to use it---and if @code{mmap} doesn't work, fall back on
|
|
|
2575 doing the job in another way using @code{read} and @code{write}.
|
|
|
2576
|
|
|
2577 The reason this precaution is needed is that the GNU kernel (the HURD)
|
|
|
2578 provides a user-extensible file system, in which there can be many
|
|
|
2579 different kinds of ``ordinary files.'' Many of them support
|
|
|
2580 @code{mmap}, but some do not. It is important to make programs handle
|
|
|
2581 all these kinds of files.
|
|
|
2582
|
|
|
2583 @node Documentation
|
|
|
2584 @chapter Documenting Programs
|
|
|
2585
|
|
|
2586 @menu
|
|
|
2587 * GNU Manuals:: Writing proper manuals.
|
|
|
2588 * Manual Structure Details:: Specific structure conventions.
|
|
|
2589 * License for Manuals:: Writing the distribution terms for a manual.
|
|
|
2590 * NEWS File:: NEWS files supplement manuals.
|
|
|
2591 * Change Logs:: Recording Changes
|
|
|
2592 * Man Pages:: Man pages are secondary.
|
|
|
2593 * Reading other Manuals:: How far you can go in learning
|
|
|
2594 from other manuals.
|
|
|
2595 @end menu
|
|
|
2596
|
|
|
2597 @node GNU Manuals
|
|
|
2598 @section GNU Manuals
|
|
|
2599
|
|
|
2600 The preferred way to document part of the GNU system is to write a
|
|
|
2601 manual in the Texinfo formatting language. This makes it possible to
|
|
|
2602 produce a good quality formatted book, using @TeX{}, and to generate an
|
|
|
2603 Info file. It is also possible to generate HTML output from Texinfo
|
|
|
2604 source. See the Texinfo manual, either the hardcopy, or the on-line
|
|
|
2605 version available through @code{info} or the Emacs Info subsystem
|
|
|
2606 (@kbd{C-h i}).
|
|
|
2607
|
|
|
2608 Programmers often find it most natural to structure the documentation
|
|
|
2609 following the structure of the implementation, which they know. But
|
|
|
2610 this structure is not necessarily good for explaining how to use the
|
|
|
2611 program; it may be irrelevant and confusing for a user.
|
|
|
2612
|
|
|
2613 At every level, from the sentences in a paragraph to the grouping of
|
|
|
2614 topics into separate manuals, the right way to structure documentation
|
|
|
2615 is according to the concepts and questions that a user will have in mind
|
|
|
2616 when reading it. Sometimes this structure of ideas matches the
|
|
|
2617 structure of the implementation of the software being documented---but
|
|
|
2618 often they are different. Often the most important part of learning to
|
|
|
2619 write good documentation is learning to notice when you are structuring
|
|
|
2620 the documentation like the implementation, and think about better
|
|
|
2621 alternatives.
|
|
|
2622
|
|
|
2623 For example, each program in the GNU system probably ought to be
|
|
|
2624 documented in one manual; but this does not mean each program should
|
|
|
2625 have its own manual. That would be following the structure of the
|
|
|
2626 implementation, rather than the structure that helps the user
|
|
|
2627 understand.
|
|
|
2628
|
|
|
2629 Instead, each manual should cover a coherent @emph{topic}. For example,
|
|
|
2630 instead of a manual for @code{diff} and a manual for @code{diff3}, we
|
|
|
2631 have one manual for ``comparison of files'' which covers both of those
|
|
|
2632 programs, as well as @code{cmp}. By documenting these programs
|
|
|
2633 together, we can make the whole subject clearer.
|
|
|
2634
|
|
|
2635 The manual which discusses a program should document all of the
|
|
|
2636 program's command-line options and all of its commands. It should give
|
|
|
2637 examples of their use. But don't organize the manual as a list of
|
|
|
2638 features. Instead, organize it logically, by subtopics. Address the
|
|
|
2639 questions that a user will ask when thinking about the job that the
|
|
|
2640 program does.
|
|
|
2641
|
|
|
2642 In general, a GNU manual should serve both as tutorial and reference.
|
|
|
2643 It should be set up for convenient access to each topic through Info,
|
|
|
2644 and for reading straight through (appendixes aside). A GNU manual
|
|
|
2645 should give a good introduction to a beginner reading through from the
|
|
|
2646 start, and should also provide all the details that hackers want.
|
|
|
2647 The Bison manual is a good example of this---please take a look at it
|
|
|
2648 to see what we mean.
|
|
|
2649
|
|
|
2650 That is not as hard as it first sounds. Arrange each chapter as a
|
|
|
2651 logical breakdown of its topic, but order the sections, and write their
|
|
|
2652 text, so that reading the chapter straight through makes sense. Do
|
|
|
2653 likewise when structuring the book into chapters, and when structuring a
|
|
|
2654 section into paragraphs. The watchword is, @emph{at each point, address
|
|
|
2655 the most fundamental and important issue raised by the preceding text.}
|
|
|
2656
|
|
|
2657 If necessary, add extra chapters at the beginning of the manual which
|
|
|
2658 are purely tutorial and cover the basics of the subject. These provide
|
|
|
2659 the framework for a beginner to understand the rest of the manual. The
|
|
|
2660 Bison manual provides a good example of how to do this.
|
|
|
2661
|
|
|
2662 Don't use Unix man pages as a model for how to write GNU documentation;
|
|
|
2663 most of them are terse, badly structured, and give inadequate
|
|
|
2664 explanation of the underlying concepts. (There are, of course
|
|
|
2665 exceptions.) Also Unix man pages use a particular format which is
|
|
|
2666 different from what we use in GNU manuals.
|
|
|
2667
|
|
|
2668 Please include an email address in the manual for where to report
|
|
|
2669 bugs @emph{in the manual}.
|
|
|
2670
|
|
|
2671 Please do not use the term ``pathname'' that is used in Unix
|
|
|
2672 documentation; use ``file name'' (two words) instead. We use the term
|
|
|
2673 ``path'' only for search paths, which are lists of directory names.
|
|
|
2674
|
|
|
2675 Please do not use the term ``illegal'' to refer to erroneous input to a
|
|
|
2676 computer program. Please use ``invalid'' for this, and reserve the term
|
|
|
2677 ``illegal'' for violations of law.
|
|
|
2678
|
|
|
2679 @node Manual Structure Details
|
|
|
2680 @section Manual Structure Details
|
|
|
2681
|
|
|
2682 The title page of the manual should state the version of the programs or
|
|
|
2683 packages documented in the manual. The Top node of the manual should
|
|
|
2684 also contain this information. If the manual is changing more
|
|
|
2685 frequently than or independent of the program, also state a version
|
|
|
2686 number for the manual in both of these places.
|
|
|
2687
|
|
|
2688 Each program documented in the manual should have a node named
|
|
|
2689 @samp{@var{program} Invocation} or @samp{Invoking @var{program}}. This
|
|
|
2690 node (together with its subnodes, if any) should describe the program's
|
|
|
2691 command line arguments and how to run it (the sort of information people
|
|
|
2692 would look in a man page for). Start with an @samp{@@example}
|
|
|
2693 containing a template for all the options and arguments that the program
|
|
|
2694 uses.
|
|
|
2695
|
|
|
2696 Alternatively, put a menu item in some menu whose item name fits one of
|
|
|
2697 the above patterns. This identifies the node which that item points to
|
|
|
2698 as the node for this purpose, regardless of the node's actual name.
|
|
|
2699
|
|
|
2700 There will be automatic features for specifying a program name and
|
|
|
2701 quickly reading just this part of its manual.
|
|
|
2702
|
|
|
2703 If one manual describes several programs, it should have such a node for
|
|
|
2704 each program described.
|
|
|
2705
|
|
|
2706 @node License for Manuals
|
|
|
2707 @section License for Manuals
|
|
|
2708
|
|
|
2709 If the manual contains a copy of the GNU GPL or GNU LGPL, or if it
|
|
|
2710 contains chapters that make political or personal statements, please
|
|
|
2711 copy the distribution terms of the GNU Emacs Manual, and adapt it by
|
|
|
2712 modifying appropriately the list of special chapters that may not be
|
|
|
2713 modified or deleted.
|
|
|
2714
|
|
|
2715 If the manual does not contain any such chapters, then imitate the
|
|
|
2716 simpler distribution terms of the Texinfo manual.
|
|
|
2717
|
|
|
2718 @node NEWS File
|
|
|
2719 @section The NEWS File
|
|
|
2720
|
|
|
2721 In addition to its manual, the package should have a file named
|
|
|
2722 @file{NEWS} which contains a list of user-visible changes worth
|
|
|
2723 mentioning. In each new release, add items to the front of the file and
|
|
|
2724 identify the version they pertain to. Don't discard old items; leave
|
|
|
2725 them in the file after the newer items. This way, a user upgrading from
|
|
|
2726 any previous version can see what is new.
|
|
|
2727
|
|
|
2728 If the @file{NEWS} file gets very long, move some of the older items
|
|
|
2729 into a file named @file{ONEWS} and put a note at the end referring the
|
|
|
2730 user to that file.
|
|
|
2731
|
|
|
2732 @node Change Logs
|
|
|
2733 @section Change Logs
|
|
|
2734
|
|
|
2735 Keep a change log to describe all the changes made to program source
|
|
|
2736 files. The purpose of this is so that people investigating bugs in the
|
|
|
2737 future will know about the changes that might have introduced the bug.
|
|
|
2738 Often a new bug can be found by looking at what was recently changed.
|
|
|
2739 More importantly, change logs can help you eliminate conceptual
|
|
|
2740 inconsistencies between different parts of a program, by giving you a
|
|
|
2741 history of how the conflicting concepts arose and who they came from.
|
|
|
2742
|
|
|
2743 @menu
|
|
|
2744 * Change Log Concepts::
|
|
|
2745 * Style of Change Logs::
|
|
|
2746 * Simple Changes::
|
|
|
2747 * Conditional Changes::
|
|
|
2748 @end menu
|
|
|
2749
|
|
|
2750 @node Change Log Concepts
|
|
|
2751 @subsection Change Log Concepts
|
|
|
2752
|
|
|
2753 You can think of the change log as a conceptual ``undo list'' which
|
|
|
2754 explains how earlier versions were different from the current version.
|
|
|
2755 People can see the current version; they don't need the change log
|
|
|
2756 to tell them what is in it. What they want from a change log is a
|
|
|
2757 clear explanation of how the earlier version differed.
|
|
|
2758
|
|
|
2759 The change log file is normally called @file{ChangeLog} and covers an
|
|
|
2760 entire directory. Each directory can have its own change log, or a
|
|
|
2761 directory can use the change log of its parent directory--it's up to
|
|
|
2762 you.
|
|
|
2763
|
|
|
2764 Another alternative is to record change log information with a version
|
|
|
2765 control system such as RCS or CVS. This can be converted automatically
|
|
|
2766 to a @file{ChangeLog} file using @code{rcs2log}; in Emacs, the command
|
|
|
2767 @kbd{C-x v a} (@code{vc-update-change-log}) does the job.
|
|
|
2768
|
|
|
2769 There's no need to describe the full purpose of the changes or how they
|
|
|
2770 work together. If you think that a change calls for explanation, you're
|
|
|
2771 probably right. Please do explain it---but please put the explanation
|
|
|
2772 in comments in the code, where people will see it whenever they see the
|
|
|
2773 code. For example, ``New function'' is enough for the change log when
|
|
|
2774 you add a function, because there should be a comment before the
|
|
|
2775 function definition to explain what it does.
|
|
|
2776
|
|
|
2777 However, sometimes it is useful to write one line to describe the
|
|
|
2778 overall purpose of a batch of changes.
|
|
|
2779
|
|
|
2780 The easiest way to add an entry to @file{ChangeLog} is with the Emacs
|
|
|
2781 command @kbd{M-x add-change-log-entry}. An entry should have an
|
|
|
2782 asterisk, the name of the changed file, and then in parentheses the name
|
|
|
2783 of the changed functions, variables or whatever, followed by a colon.
|
|
|
2784 Then describe the changes you made to that function or variable.
|
|
|
2785
|
|
|
2786 @node Style of Change Logs
|
|
|
2787 @subsection Style of Change Logs
|
|
|
2788
|
|
|
2789 Here are some examples of change log entries:
|
|
|
2790
|
|
|
2791 @example
|
|
|
2792 * register.el (insert-register): Return nil.
|
|
|
2793 (jump-to-register): Likewise.
|
|
|
2794
|
|
|
2795 * sort.el (sort-subr): Return nil.
|
|
|
2796
|
|
|
2797 * tex-mode.el (tex-bibtex-file, tex-file, tex-region):
|
|
|
2798 Restart the tex shell if process is gone or stopped.
|
|
|
2799 (tex-shell-running): New function.
|
|
|
2800
|
|
|
2801 * expr.c (store_one_arg): Round size up for move_block_to_reg.
|
|
|
2802 (expand_call): Round up when emitting USE insns.
|
|
|
2803 * stmt.c (assign_parms): Round size up for move_block_from_reg.
|
|
|
2804 @end example
|
|
|
2805
|
|
|
2806 It's important to name the changed function or variable in full. Don't
|
|
|
2807 abbreviate function or variable names, and don't combine them.
|
|
|
2808 Subsequent maintainers will often search for a function name to find all
|
|
|
2809 the change log entries that pertain to it; if you abbreviate the name,
|
|
|
2810 they won't find it when they search.
|
|
|
2811
|
|
|
2812 For example, some people are tempted to abbreviate groups of function
|
|
|
2813 names by writing @samp{* register.el (@{insert,jump-to@}-register)};
|
|
|
2814 this is not a good idea, since searching for @code{jump-to-register} or
|
|
|
2815 @code{insert-register} would not find that entry.
|
|
|
2816
|
|
|
2817 Separate unrelated change log entries with blank lines. When two
|
|
|
2818 entries represent parts of the same change, so that they work together,
|
|
|
2819 then don't put blank lines between them. Then you can omit the file
|
|
|
2820 name and the asterisk when successive entries are in the same file.
|
|
|
2821
|
|
|
2822 @node Simple Changes
|
|
|
2823 @subsection Simple Changes
|
|
|
2824
|
|
|
2825 Certain simple kinds of changes don't need much detail in the change
|
|
|
2826 log.
|
|
|
2827
|
|
|
2828 When you change the calling sequence of a function in a simple fashion,
|
|
|
2829 and you change all the callers of the function, there is no need to make
|
|
|
2830 individual entries for all the callers that you changed. Just write in
|
|
|
2831 the entry for the function being called, ``All callers changed.''
|
|
|
2832
|
|
|
2833 @example
|
|
|
2834 * keyboard.c (Fcommand_execute): New arg SPECIAL.
|
|
|
2835 All callers changed.
|
|
|
2836 @end example
|
|
|
2837
|
|
|
2838 When you change just comments or doc strings, it is enough to write an
|
|
|
2839 entry for the file, without mentioning the functions. Just ``Doc
|
|
|
2840 fixes'' is enough for the change log.
|
|
|
2841
|
|
|
2842 There's no need to make change log entries for documentation files.
|
|
|
2843 This is because documentation is not susceptible to bugs that are hard
|
|
|
2844 to fix. Documentation does not consist of parts that must interact in a
|
|
|
2845 precisely engineered fashion. To correct an error, you need not know
|
|
|
2846 the history of the erroneous passage; it is enough to compare what the
|
|
|
2847 documentation says with the way the program actually works.
|
|
|
2848
|
|
|
2849 @node Conditional Changes
|
|
|
2850 @subsection Conditional Changes
|
|
|
2851
|
|
|
2852 C programs often contain compile-time @code{#if} conditionals. Many
|
|
|
2853 changes are conditional; sometimes you add a new definition which is
|
|
|
2854 entirely contained in a conditional. It is very useful to indicate in
|
|
|
2855 the change log the conditions for which the change applies.
|
|
|
2856
|
|
|
2857 Our convention for indicating conditional changes is to use square
|
|
|
2858 brackets around the name of the condition.
|
|
|
2859
|
|
|
2860 Here is a simple example, describing a change which is conditional but
|
|
|
2861 does not have a function or entity name associated with it:
|
|
|
2862
|
|
|
2863 @example
|
|
|
2864 * xterm.c [SOLARIS2]: Include string.h.
|
|
|
2865 @end example
|
|
|
2866
|
|
|
2867 Here is an entry describing a new definition which is entirely
|
|
|
2868 conditional. This new definition for the macro @code{FRAME_WINDOW_P} is
|
|
|
2869 used only when @code{HAVE_X_WINDOWS} is defined:
|
|
|
2870
|
|
|
2871 @example
|
|
|
2872 * frame.h [HAVE_X_WINDOWS] (FRAME_WINDOW_P): Macro defined.
|
|
|
2873 @end example
|
|
|
2874
|
|
|
2875 Here is an entry for a change within the function @code{init_display},
|
|
|
2876 whose definition as a whole is unconditional, but the changes themselves
|
|
|
2877 are contained in a @samp{#ifdef HAVE_LIBNCURSES} conditional:
|
|
|
2878
|
|
|
2879 @example
|
|
|
2880 * dispnew.c (init_display) [HAVE_LIBNCURSES]: If X, call tgetent.
|
|
|
2881 @end example
|
|
|
2882
|
|
|
2883 Here is an entry for a change that takes affect only when
|
|
|
2884 a certain macro is @emph{not} defined:
|
|
|
2885
|
|
|
2886 @example
|
|
|
2887 (gethostname) [!HAVE_SOCKETS]: Replace with winsock version.
|
|
|
2888 @end example
|
|
|
2889
|
|
|
2890 @node Man Pages
|
|
|
2891 @section Man Pages
|
|
|
2892
|
|
|
2893 In the GNU project, man pages are secondary. It is not necessary or
|
|
|
2894 expected for every GNU program to have a man page, but some of them do.
|
|
|
2895 It's your choice whether to include a man page in your program.
|
|
|
2896
|
|
|
2897 When you make this decision, consider that supporting a man page
|
|
|
2898 requires continual effort each time the program is changed. The time
|
|
|
2899 you spend on the man page is time taken away from more useful work.
|
|
|
2900
|
|
|
2901 For a simple program which changes little, updating the man page may be
|
|
|
2902 a small job. Then there is little reason not to include a man page, if
|
|
|
2903 you have one.
|
|
|
2904
|
|
|
2905 For a large program that changes a great deal, updating a man page may
|
|
|
2906 be a substantial burden. If a user offers to donate a man page, you may
|
|
|
2907 find this gift costly to accept. It may be better to refuse the man
|
|
|
2908 page unless the same person agrees to take full responsibility for
|
|
|
2909 maintaining it---so that you can wash your hands of it entirely. If
|
|
|
2910 this volunteer later ceases to do the job, then don't feel obliged to
|
|
|
2911 pick it up yourself; it may be better to withdraw the man page from the
|
|
|
2912 distribution until someone else agrees to update it.
|
|
|
2913
|
|
|
2914 When a program changes only a little, you may feel that the
|
|
|
2915 discrepancies are small enough that the man page remains useful without
|
|
|
2916 updating. If so, put a prominent note near the beginning of the man
|
|
|
2917 page explaining that you don't maintain it and that the Texinfo manual
|
|
|
2918 is more authoritative. The note should say how to access the Texinfo
|
|
|
2919 documentation.
|
|
|
2920
|
|
|
2921 @node Reading other Manuals
|
|
|
2922 @section Reading other Manuals
|
|
|
2923
|
|
|
2924 There may be non-free books or documentation files that describe the
|
|
|
2925 program you are documenting.
|
|
|
2926
|
|
|
2927 It is ok to use these documents for reference, just as the author of a
|
|
|
2928 new algebra textbook can read other books on algebra. A large portion
|
|
|
2929 of any non-fiction book consists of facts, in this case facts about how
|
|
|
2930 a certain program works, and these facts are necessarily the same for
|
|
|
2931 everyone who writes about the subject. But be careful not to copy your
|
|
|
2932 outline structure, wording, tables or examples from preexisting non-free
|
|
|
2933 documentation. Copying from free documentation may be ok; please check
|
|
|
2934 with the FSF about the individual case.
|
|
|
2935
|
|
|
2936 @node Managing Releases
|
|
|
2937 @chapter The Release Process
|
|
|
2938
|
|
|
2939 Making a release is more than just bundling up your source files in a
|
|
|
2940 tar file and putting it up for FTP. You should set up your software so
|
|
|
2941 that it can be configured to run on a variety of systems. Your Makefile
|
|
|
2942 should conform to the GNU standards described below, and your directory
|
|
|
2943 layout should also conform to the standards discussed below. Doing so
|
|
|
2944 makes it easy to include your package into the larger framework of
|
|
|
2945 all GNU software.
|
|
|
2946
|
|
|
2947 @menu
|
|
|
2948 * Configuration:: How Configuration Should Work
|
|
|
2949 * Makefile Conventions:: Makefile Conventions
|
|
|
2950 * Releases:: Making Releases
|
|
|
2951 @end menu
|
|
|
2952
|
|
|
2953 @node Configuration
|
|
|
2954 @section How Configuration Should Work
|
|
|
2955
|
|
|
2956 Each GNU distribution should come with a shell script named
|
|
|
2957 @code{configure}. This script is given arguments which describe the
|
|
|
2958 kind of machine and system you want to compile the program for.
|
|
|
2959
|
|
|
2960 The @code{configure} script must record the configuration options so
|
|
|
2961 that they affect compilation.
|
|
|
2962
|
|
|
2963 One way to do this is to make a link from a standard name such as
|
|
|
2964 @file{config.h} to the proper configuration file for the chosen system.
|
|
|
2965 If you use this technique, the distribution should @emph{not} contain a
|
|
|
2966 file named @file{config.h}. This is so that people won't be able to
|
|
|
2967 build the program without configuring it first.
|
|
|
2968
|
|
|
2969 Another thing that @code{configure} can do is to edit the Makefile. If
|
|
|
2970 you do this, the distribution should @emph{not} contain a file named
|
|
|
2971 @file{Makefile}. Instead, it should include a file @file{Makefile.in} which
|
|
|
2972 contains the input used for editing. Once again, this is so that people
|
|
|
2973 won't be able to build the program without configuring it first.
|
|
|
2974
|
|
|
2975 If @code{configure} does write the @file{Makefile}, then @file{Makefile}
|
|
|
2976 should have a target named @file{Makefile} which causes @code{configure}
|
|
|
2977 to be rerun, setting up the same configuration that was set up last
|
|
|
2978 time. The files that @code{configure} reads should be listed as
|
|
|
2979 dependencies of @file{Makefile}.
|
|
|
2980
|
|
|
2981 All the files which are output from the @code{configure} script should
|
|
|
2982 have comments at the beginning explaining that they were generated
|
|
|
2983 automatically using @code{configure}. This is so that users won't think
|
|
|
2984 of trying to edit them by hand.
|
|
|
2985
|
|
|
2986 The @code{configure} script should write a file named @file{config.status}
|
|
|
2987 which describes which configuration options were specified when the
|
|
|
2988 program was last configured. This file should be a shell script which,
|
|
|
2989 if run, will recreate the same configuration.
|
|
|
2990
|
|
|
2991 The @code{configure} script should accept an option of the form
|
|
|
2992 @samp{--srcdir=@var{dirname}} to specify the directory where sources are found
|
|
|
2993 (if it is not the current directory). This makes it possible to build
|
|
|
2994 the program in a separate directory, so that the actual source directory
|
|
|
2995 is not modified.
|
|
|
2996
|
|
|
2997 If the user does not specify @samp{--srcdir}, then @code{configure} should
|
|
|
2998 check both @file{.} and @file{..} to see if it can find the sources. If
|
|
|
2999 it finds the sources in one of these places, it should use them from
|
|
|
3000 there. Otherwise, it should report that it cannot find the sources, and
|
|
|
3001 should exit with nonzero status.
|
|
|
3002
|
|
|
3003 Usually the easy way to support @samp{--srcdir} is by editing a
|
|
|
3004 definition of @code{VPATH} into the Makefile. Some rules may need to
|
|
|
3005 refer explicitly to the specified source directory. To make this
|
|
|
3006 possible, @code{configure} can add to the Makefile a variable named
|
|
|
3007 @code{srcdir} whose value is precisely the specified directory.
|
|
|
3008
|
|
|
3009 The @code{configure} script should also take an argument which specifies the
|
|
|
3010 type of system to build the program for. This argument should look like
|
|
|
3011 this:
|
|
|
3012
|
|
|
3013 @example
|
|
|
3014 @var{cpu}-@var{company}-@var{system}
|
|
|
3015 @end example
|
|
|
3016
|
|
|
3017 For example, a Sun 3 might be @samp{m68k-sun-sunos4.1}.
|
|
|
3018
|
|
|
3019 The @code{configure} script needs to be able to decode all plausible
|
|
|
3020 alternatives for how to describe a machine. Thus, @samp{sun3-sunos4.1}
|
|
|
3021 would be a valid alias. For many programs, @samp{vax-dec-ultrix} would
|
|
|
3022 be an alias for @samp{vax-dec-bsd}, simply because the differences
|
|
|
3023 between Ultrix and BSD are rarely noticeable, but a few programs
|
|
|
3024 might need to distinguish them.
|
|
|
3025 @c Real 4.4BSD now runs on some Suns.
|
|
|
3026
|
|
|
3027 There is a shell script called @file{config.sub} that you can use
|
|
|
3028 as a subroutine to validate system types and canonicalize aliases.
|
|
|
3029
|
|
|
3030 Other options are permitted to specify in more detail the software
|
|
|
3031 or hardware present on the machine, and include or exclude optional
|
|
|
3032 parts of the package:
|
|
|
3033
|
|
|
3034 @table @samp
|
|
|
3035 @item --enable-@var{feature}@r{[}=@var{parameter}@r{]}
|
|
|
3036 Configure the package to build and install an optional user-level
|
|
|
3037 facility called @var{feature}. This allows users to choose which
|
|
|
3038 optional features to include. Giving an optional @var{parameter} of
|
|
|
3039 @samp{no} should omit @var{feature}, if it is built by default.
|
|
|
3040
|
|
|
3041 No @samp{--enable} option should @strong{ever} cause one feature to
|
|
|
3042 replace another. No @samp{--enable} option should ever substitute one
|
|
|
3043 useful behavior for another useful behavior. The only proper use for
|
|
|
3044 @samp{--enable} is for questions of whether to build part of the program
|
|
|
3045 or exclude it.
|
|
|
3046
|
|
|
3047 @item --with-@var{package}
|
|
|
3048 @c @r{[}=@var{parameter}@r{]}
|
|
|
3049 The package @var{package} will be installed, so configure this package
|
|
|
3050 to work with @var{package}.
|
|
|
3051
|
|
|
3052 @c Giving an optional @var{parameter} of
|
|
|
3053 @c @samp{no} should omit @var{package}, if it is used by default.
|
|
|
3054
|
|
|
3055 Possible values of @var{package} include
|
|
|
3056 @samp{gnu-as} (or @samp{gas}), @samp{gnu-ld}, @samp{gnu-libc},
|
|
|
3057 @samp{gdb},
|
|
|
3058 @samp{x},
|
|
|
3059 and
|
|
|
3060 @samp{x-toolkit}.
|
|
|
3061
|
|
|
3062 Do not use a @samp{--with} option to specify the file name to use to
|
|
|
3063 find certain files. That is outside the scope of what @samp{--with}
|
|
|
3064 options are for.
|
|
|
3065
|
|
|
3066 @item --nfp
|
|
|
3067 The target machine has no floating point processor.
|
|
|
3068
|
|
|
3069 @item --gas
|
|
|
3070 The target machine assembler is GAS, the GNU assembler.
|
|
|
3071 This is obsolete; users should use @samp{--with-gnu-as} instead.
|
|
|
3072
|
|
|
3073 @item --x
|
|
|
3074 The target machine has the X Window System installed.
|
|
|
3075 This is obsolete; users should use @samp{--with-x} instead.
|
|
|
3076 @end table
|
|
|
3077
|
|
|
3078 All @code{configure} scripts should accept all of these ``detail''
|
|
|
3079 options, whether or not they make any difference to the particular
|
|
|
3080 package at hand. In particular, they should accept any option that
|
|
|
3081 starts with @samp{--with-} or @samp{--enable-}. This is so users will
|
|
|
3082 be able to configure an entire GNU source tree at once with a single set
|
|
|
3083 of options.
|
|
|
3084
|
|
|
3085 You will note that the categories @samp{--with-} and @samp{--enable-}
|
|
|
3086 are narrow: they @strong{do not} provide a place for any sort of option
|
|
|
3087 you might think of. That is deliberate. We want to limit the possible
|
|
|
3088 configuration options in GNU software. We do not want GNU programs to
|
|
|
3089 have idiosyncratic configuration options.
|
|
|
3090
|
|
|
3091 Packages that perform part of the compilation process may support cross-compilation.
|
|
|
3092 In such a case, the host and target machines for the program may be
|
|
|
3093 different. The @code{configure} script should normally treat the
|
|
|
3094 specified type of system as both the host and the target, thus producing
|
|
|
3095 a program which works for the same type of machine that it runs on.
|
|
|
3096
|
|
|
3097 The way to build a cross-compiler, cross-assembler, or what have you, is
|
|
|
3098 to specify the option @samp{--host=@var{hosttype}} when running
|
|
|
3099 @code{configure}. This specifies the host system without changing the
|
|
|
3100 type of target system. The syntax for @var{hosttype} is the same as
|
|
|
3101 described above.
|
|
|
3102
|
|
|
3103 Bootstrapping a cross-compiler requires compiling it on a machine other
|
|
|
3104 than the host it will run on. Compilation packages accept a
|
|
|
3105 configuration option @samp{--build=@var{hosttype}} for specifying the
|
|
|
3106 configuration on which you will compile them, in case that is different
|
|
|
3107 from the host.
|
|
|
3108
|
|
|
3109 Programs for which cross-operation is not meaningful need not accept the
|
|
|
3110 @samp{--host} option, because configuring an entire operating system for
|
|
|
3111 cross-operation is not a meaningful thing.
|
|
|
3112
|
|
|
3113 Some programs have ways of configuring themselves automatically. If
|
|
|
3114 your program is set up to do this, your @code{configure} script can simply
|
|
|
3115 ignore most of its arguments.
|
|
|
3116
|
|
|
3117 @comment The makefile standards are in a separate file that is also
|
|
|
3118 @comment included by make.texinfo. Done by roland@gnu.ai.mit.edu on 1/6/93.
|
|
|
3119 @comment For this document, turn chapters into sections, etc.
|
|
|
3120 @lowersections
|
|
|
3121 @include make-stds.texi
|
|
|
3122 @raisesections
|
|
|
3123
|
|
|
3124 @node Releases
|
|
|
3125 @section Making Releases
|
|
|
3126
|
|
|
3127 Package the distribution of @code{Foo version 69.96} up in a gzipped tar
|
|
|
3128 file with the name @file{foo-69.96.tar.gz}. It should unpack into a
|
|
|
3129 subdirectory named @file{foo-69.96}.
|
|
|
3130
|
|
|
3131 Building and installing the program should never modify any of the files
|
|
|
3132 contained in the distribution. This means that all the files that form
|
|
|
3133 part of the program in any way must be classified into @dfn{source
|
|
|
3134 files} and @dfn{non-source files}. Source files are written by humans
|
|
|
3135 and never changed automatically; non-source files are produced from
|
|
|
3136 source files by programs under the control of the Makefile.
|
|
|
3137
|
|
|
3138 The distribution should contain a file named @file{README} which gives
|
|
|
3139 the name of the package, and a general description of what it does. It
|
|
|
3140 is also good to explain the purpose of each of the first-level
|
|
|
3141 subdirectories in the package, if there are any. The @file{README} file
|
|
|
3142 should either state the version number of the package, or refer to where
|
|
|
3143 in the package it can be found.
|
|
|
3144
|
|
|
3145 The @file{README} file should refer to the file @file{INSTALL}, which
|
|
|
3146 should contain an explanation of the installation procedure.
|
|
|
3147
|
|
|
3148 The @file{README} file should also refer to the file which contains the
|
|
|
3149 copying conditions. The GNU GPL, if used, should be in a file called
|
|
|
3150 @file{COPYING}. If the GNU LGPL is used, it should be in a file called
|
|
|
3151 @file{COPYING.LIB}.
|
|
|
3152
|
|
|
3153 Naturally, all the source files must be in the distribution. It is okay
|
|
|
3154 to include non-source files in the distribution, provided they are
|
|
|
3155 up-to-date and machine-independent, so that building the distribution
|
|
|
3156 normally will never modify them. We commonly include non-source files
|
|
|
3157 produced by Bison, @code{lex}, @TeX{}, and @code{makeinfo}; this helps avoid
|
|
|
3158 unnecessary dependencies between our distributions, so that users can
|
|
|
3159 install whichever packages they want to install.
|
|
|
3160
|
|
|
3161 Non-source files that might actually be modified by building and
|
|
|
3162 installing the program should @strong{never} be included in the
|
|
|
3163 distribution. So if you do distribute non-source files, always make
|
|
|
3164 sure they are up to date when you make a new distribution.
|
|
|
3165
|
|
|
3166 Make sure that the directory into which the distribution unpacks (as
|
|
|
3167 well as any subdirectories) are all world-writable (octal mode 777).
|
|
|
3168 This is so that old versions of @code{tar} which preserve the
|
|
|
3169 ownership and permissions of the files from the tar archive will be
|
|
|
3170 able to extract all the files even if the user is unprivileged.
|
|
|
3171
|
|
|
3172 Make sure that all the files in the distribution are world-readable.
|
|
|
3173
|
|
|
3174 Make sure that no file name in the distribution is more than 14
|
|
|
3175 characters long. Likewise, no file created by building the program
|
|
|
3176 should have a name longer than 14 characters. The reason for this is
|
|
|
3177 that some systems adhere to a foolish interpretation of the @sc{posix}
|
|
|
3178 standard, and refuse to open a longer name, rather than truncating as
|
|
|
3179 they did in the past.
|
|
|
3180
|
|
|
3181 Don't include any symbolic links in the distribution itself. If the tar
|
|
|
3182 file contains symbolic links, then people cannot even unpack it on
|
|
|
3183 systems that don't support symbolic links. Also, don't use multiple
|
|
|
3184 names for one file in different directories, because certain file
|
|
|
3185 systems cannot handle this and that prevents unpacking the
|
|
|
3186 distribution.
|
|
|
3187
|
|
|
3188 Try to make sure that all the file names will be unique on MS-DOS. A
|
|
|
3189 name on MS-DOS consists of up to 8 characters, optionally followed by a
|
|
|
3190 period and up to three characters. MS-DOS will truncate extra
|
|
|
3191 characters both before and after the period. Thus,
|
|
|
3192 @file{foobarhacker.c} and @file{foobarhacker.o} are not ambiguous; they
|
|
|
3193 are truncated to @file{foobarha.c} and @file{foobarha.o}, which are
|
|
|
3194 distinct.
|
|
|
3195
|
|
|
3196 Include in your distribution a copy of the @file{texinfo.tex} you used
|
|
|
3197 to test print any @file{*.texinfo} or @file{*.texi} files.
|
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|
3198
|
|
|
3199 Likewise, if your program uses small GNU software packages like regex,
|
|
|
3200 getopt, obstack, or termcap, include them in the distribution file.
|
|
|
3201 Leaving them out would make the distribution file a little smaller at
|
|
|
3202 the expense of possible inconvenience to a user who doesn't know what
|
|
|
3203 other files to get.
|
|
|
3204
|
|
|
3205 @node References
|
|
|
3206 @chapter References to Non-Free Software and Documentation
|
|
|
3207
|
|
|
3208 A GNU program should not recommend use of any non-free program. We
|
|
|
3209 can't stop some people from writing proprietary programs, or stop other
|
|
|
3210 people from using them. But we can and should avoid helping to
|
|
|
3211 advertise them to new customers.
|
|
|
3212
|
|
|
3213 Sometimes it is important to mention how to build your package on top of
|
|
|
3214 some non-free operating system or other non-free base package. In such
|
|
|
3215 cases, please mention the name of the non-free package or system in the
|
|
|
3216 briefest possible way. Don't include any references for where to find
|
|
|
3217 more information about the proprietary program. The goal should be that
|
|
|
3218 people already using the proprietary program will get the advice they
|
|
|
3219 need about how to use your free program, while people who don't already
|
|
|
3220 use the proprietary program will not see anything to encourage them to
|
|
|
3221 take an interest in it.
|
|
|
3222
|
|
|
3223 Likewise, a GNU package should not refer the user to any non-free
|
|
|
3224 documentation for free software. The need for free documentation to go
|
|
|
3225 with free software is now a major focus of the GNU project; to show that
|
|
|
3226 we are serious about the need for free documentation, we must not
|
|
|
3227 undermine our position by recommending use of documentation that isn't
|
|
|
3228 free.
|
|
|
3229
|
|
|
3230 @contents
|
|
|
3231
|
|
|
3232 @bye
|
